[O] Removing all timeouts (mark II) (#26736)

These are essentially self-inflicted race conditions. Instead of timeouts we're going to try a more verbose logging mechanism that points out when things are taking a long time.

dev/devicelab/README.md

@@ -119,7 +119,7 @@ Notably, it will start and stop gradle, for instance.
 To run all tests defined in `manifest.yaml`, use option `-a` (`--all`):
 
 ```sh
-dart bin/run.dart -a
+../../bin/cache/dart-sdk/bin/dart bin/run.dart -a
 ```
 
 ## Running specific tests
@@ -128,7 +128,7 @@ To run a test, use option `-t` (`--task`):
 
 ```sh
 # from the .../flutter/dev/devicelab directory
-dart bin/run.dart -t {NAME_OR_PATH_OF_TEST}
+../../bin/cache/dart-sdk/bin/dart bin/run.dart -t {NAME_OR_PATH_OF_TEST}
 ```
 
 Where `NAME_OR_PATH_OF_TEST` can be either of:
@@ -142,7 +142,7 @@ Where `NAME_OR_PATH_OF_TEST` can be either of:
 To run multiple tests, repeat option `-t` (`--task`) multiple times:
 
 ```sh
-dart bin/run.dart -t test1 -t test2 -t test3
+../../bin/cache/dart-sdk/bin/dart bin/run.dart -t test1 -t test2 -t test3
 ```
 
 To run tests from a specific stage, use option `-s` (`--stage`).
@@ -151,7 +151,7 @@ Currently there are only three stages defined, `devicelab`,
 
 
 ```sh
-dart bin/run.dart -s {NAME_OF_STAGE}
+../../bin/cache/dart-sdk/bin/dart bin/run.dart -s {NAME_OF_STAGE}
 ```
 
 # Reproducing broken builds locally
@@ -162,7 +162,7 @@ failing test is `flutter_gallery__transition_perf`. This name can be passed to
 the `run.dart` command. For example:
 
 ```sh
-dart bin/run.dart -t flutter_gallery__transition_perf
+../../bin/cache/dart-sdk/bin/dart bin/run.dart -t flutter_gallery__transition_perf
 ```
 
 # Writing tests

dev/devicelab/bin/tasks/commands_test.dart

@@ -74,18 +74,18 @@ void main() {
       run.stdin.write('P');
       await driver.drive('none');
       final Future<String> reloadStartingText =
-        stdout.stream.firstWhere((String line) => line.endsWith('hot reload...'));
+        stdout.stream.firstWhere((String line) => line.endsWith('] Initializing hot reload...'));
       final Future<String> reloadEndingText =
-        stdout.stream.firstWhere((String line) => line.contains('Hot reload performed in '));
+        stdout.stream.firstWhere((String line) => line.contains('] Reloaded ') && line.endsWith('ms.'));
       print('test: pressing "r" to perform a hot reload...');
       run.stdin.write('r');
       await reloadStartingText;
       await reloadEndingText;
       await driver.drive('none');
       final Future<String> restartStartingText =
-        stdout.stream.firstWhere((String line) => line.endsWith('hot restart...'));
+        stdout.stream.firstWhere((String line) => line.endsWith('Performing hot restart...'));
       final Future<String> restartEndingText =
-        stdout.stream.firstWhere((String line) => line.contains('Hot restart performed in '));
+        stdout.stream.firstWhere((String line) => line.contains('] Restarted application in '));
       print('test: pressing "R" to perform a full reload...');
       run.stdin.write('R');
       await restartStartingText;

dev/integration_tests/external_ui/test_driver/main_test.dart

@@ -29,7 +29,7 @@ Future<void> main() async {
       final SerializableFinder summary = find.byValueKey('summary');
 
       // Wait for calibration to complete and fab to appear.
-      await driver.waitFor(fab, timeout: const Duration(seconds: 40));
+      await driver.waitFor(fab);
 
       final String calibrationResult = await driver.getText(summary);
       final Match matchCalibration = calibrationRegExp.matchAsPrefix(calibrationResult);
@@ -59,7 +59,7 @@ Future<void> main() async {
       expect(double.parse(matchFast.group(1)), closeTo(flutterFrameRate * 2.0, 5.0));
       expect(double.parse(matchFast.group(2)), closeTo(flutterFrameRate, 10.0));
       expect(int.parse(matchFast.group(3)), 1);
-    }, timeout: const Timeout(Duration(minutes: 1)));
+    });
 
     tearDownAll(() async {
       driver?.close();

packages/flutter/lib/src/widgets/binding.dart

@@ -268,8 +268,7 @@ mixin WidgetsBinding on BindingBase, SchedulerBinding, GestureBinding, RendererB
   void initServiceExtensions() {
     super.initServiceExtensions();
 
-    const bool isReleaseMode = bool.fromEnvironment('dart.vm.product');
-    if (!isReleaseMode) {
+    profile(() {
       registerSignalServiceExtension(
         name: 'debugDumpApp',
         callback: () {
@@ -294,11 +293,14 @@ mixin WidgetsBinding on BindingBase, SchedulerBinding, GestureBinding, RendererB
         name: 'didSendFirstFrameEvent',
         callback: (_) async {
           return <String, dynamic>{
+            // This is defined to return a STRING, not a boolean.
+            // Devtools, the Intellij plugin, and the flutter tool all depend
+            // on it returning a string and not a boolean.
             'enabled': _needToReportFirstFrame ? 'false' : 'true'
           };
         },
       );
-    }
+    });
 
     assert(() {
       registerBoolServiceExtension(
@@ -540,22 +542,25 @@ mixin WidgetsBinding on BindingBase, SchedulerBinding, GestureBinding, RendererB
 
   /// Whether the first frame has finished rendering.
   ///
-  /// Only valid in profile and debug builds, it can't be used in release
-  /// builds.
-  /// It can be deferred using [deferFirstFrameReport] and
-  /// [allowFirstFrameReport].
-  /// The value is set at the end of the call to [drawFrame].
+  /// Only useful in profile and debug builds; in release builds, this always
+  /// return false. This can be deferred using [deferFirstFrameReport] and
+  /// [allowFirstFrameReport]. The value is set at the end of the call to
+  /// [drawFrame].
+  ///
+  /// This value can also be obtained over the VM service protocol as
+  /// `ext.flutter.didSendFirstFrameEvent`.
   bool get debugDidSendFirstFrameEvent => !_needToReportFirstFrame;
 
   /// Tell the framework not to report the frame it is building as a "useful"
   /// first frame until there is a corresponding call to [allowFirstFrameReport].
   ///
-  /// This is used by [WidgetsApp] to report the first frame.
-  //
-  // TODO(ianh): This method should only be available in debug and profile modes.
+  /// This is used by [WidgetsApp] to avoid reporting frames that aren't useful
+  /// during startup as the "first frame".
   void deferFirstFrameReport() {
-    assert(_deferFirstFrameReportCount >= 0);
-    _deferFirstFrameReportCount += 1;
+    profile(() {
+      assert(_deferFirstFrameReportCount >= 0);
+      _deferFirstFrameReportCount += 1;
+    });
   }
 
   /// When called after [deferFirstFrameReport]: tell the framework to report
@@ -564,12 +569,13 @@ mixin WidgetsBinding on BindingBase, SchedulerBinding, GestureBinding, RendererB
   /// This method may only be called once for each corresponding call
   /// to [deferFirstFrameReport].
   ///
-  /// This is used by [WidgetsApp] to report the first frame.
-  //
-  // TODO(ianh): This method should only be available in debug and profile modes.
+  /// This is used by [WidgetsApp] to report when the first useful frame is
+  /// painted.
   void allowFirstFrameReport() {
-    assert(_deferFirstFrameReportCount >= 1);
-    _deferFirstFrameReportCount -= 1;
+    profile(() {
+      assert(_deferFirstFrameReportCount >= 1);
+      _deferFirstFrameReportCount -= 1;
+    });
   }
 
   void _handleBuildScheduled() {
@@ -691,13 +697,13 @@ mixin WidgetsBinding on BindingBase, SchedulerBinding, GestureBinding, RendererB
         return true;
       }());
     }
-    // TODO(ianh): Following code should not be included in release mode, only profile and debug modes.
-    // See https://github.com/dart-lang/sdk/issues/27192
-    if (_needToReportFirstFrame && _reportFirstFrame) {
-      developer.Timeline.instantSync('Widgets completed first useful frame');
-      developer.postEvent('Flutter.FirstFrame', <String, dynamic>{});
-      _needToReportFirstFrame = false;
-    }
+    profile(() {
+      if (_needToReportFirstFrame && _reportFirstFrame) {
+        developer.Timeline.instantSync('Widgets completed first useful frame');
+        developer.postEvent('Flutter.FirstFrame', <String, dynamic>{});
+        _needToReportFirstFrame = false;
+      }
+    });
   }
 
   /// The [Element] that is at the root of the hierarchy (and which wraps the

packages/flutter_driver/lib/src/common/message.dart

@@ -9,16 +9,24 @@ import 'package:meta/meta.dart';
 abstract class Command {
   /// Abstract const constructor. This constructor enables subclasses to provide
   /// const constructors so that they can be used in const expressions.
-  const Command({ Duration timeout })
-      : timeout = timeout ?? const Duration(seconds: 5);
+  const Command({ this.timeout });
 
   /// Deserializes this command from the value generated by [serialize].
   Command.deserialize(Map<String, String> json)
-      : timeout = Duration(milliseconds: int.parse(json['timeout']));
+      : timeout = _parseTimeout(json);
+
+  static Duration _parseTimeout(Map<String, String> json) {
+    final String timeout = json['timeout'];
+    if (timeout == null)
+      return null;
+    return Duration(milliseconds: int.parse(timeout));
+  }
 
   /// The maximum amount of time to wait for the command to complete.
   ///
-  /// Defaults to 5 seconds.
+  /// Defaults to no timeout, because it is common for operations to take oddly
+  /// long in test environments (e.g. because the test host is overloaded), and
+  /// having timeouts essentially means having race conditions.
   final Duration timeout;
 
   /// Identifies the type of the command object and of the handler.
@@ -26,10 +34,14 @@ abstract class Command {
 
   /// Serializes this command to parameter name/value pairs.
   @mustCallSuper
-  Map<String, String> serialize() => <String, String>{
-    'command': kind,
-    'timeout': '${timeout.inMilliseconds}',
-  };
+  Map<String, String> serialize() {
+    final Map<String, String> result = <String, String>{
+      'command': kind,
+    };
+    if (timeout != null)
+      result['timeout'] = '${timeout.inMilliseconds}';
+    return result;
+  }
 }
 
 /// An object sent from a Flutter application back to the Flutter Driver in

packages/flutter_driver/lib/src/driver/driver.dart

@@ -61,38 +61,13 @@ enum TimelineStream {
 
 const List<TimelineStream> _defaultStreams = <TimelineStream>[TimelineStream.all];
 
-/// Multiplies the timeout values used when establishing a connection to the
-/// Flutter app under test and obtain an instance of [FlutterDriver].
-///
-/// This multiplier applies automatically when using the default implementation
-/// of the [vmServiceConnectFunction].
-///
-/// See also:
-///
-///  * [FlutterDriver.timeoutMultiplier], which multiplies all command timeouts by this number.
-double connectionTimeoutMultiplier = _kDefaultTimeoutMultiplier;
-
-const double _kDefaultTimeoutMultiplier = 1.0;
-
-/// Default timeout for short-running RPCs.
-Duration _shortTimeout(double multiplier) => const Duration(seconds: 5) * multiplier;
-
-/// Default timeout for awaiting an Isolate to become runnable.
-Duration _isolateLoadRunnableTimeout(double multiplier) => const Duration(minutes: 1) * multiplier;
-
-/// Time to delay before driving a Fuchsia module.
-Duration _fuchsiaDriveDelay(double multiplier) => const Duration(milliseconds: 500) * multiplier;
-
-/// Default timeout for long-running RPCs.
-Duration _longTimeout(double multiplier) => _shortTimeout(multiplier) * 6;
-
-/// Additional amount of time we give the command to finish or timeout remotely
-/// before timing out locally.
-Duration _rpcGraceTime(double multiplier) => _shortTimeout(multiplier) ~/ 2;
+/// How long to wait before showing a message saying that
+/// things seem to be taking a long time.
+const Duration _kUnusuallyLongTimeout = Duration(seconds: 5);
 
 /// The amount of time we wait prior to making the next attempt to connect to
 /// the VM service.
-Duration _pauseBetweenReconnectAttempts(double multiplier) => _shortTimeout(multiplier) ~/ 5;
+const Duration _kPauseBetweenReconnectAttempts = Duration(seconds: 1);
 
 // See https://github.com/dart-lang/sdk/blob/master/runtime/vm/timeline.cc#L32
 String _timelineStreamsToString(List<TimelineStream> streams) {
@@ -116,6 +91,27 @@ String _timelineStreamsToString(List<TimelineStream> streams) {
 
 final Logger _log = Logger('FlutterDriver');
 
+Future<T> _warnIfSlow<T>({
+  @required Future<T> future,
+  @required Duration timeout,
+  @required String message,
+}) {
+  assert(future != null);
+  assert(timeout != null);
+  assert(message != null);
+  return future..timeout(timeout, onTimeout: () { _log.warning(message); });
+}
+
+Duration _maxDuration(Duration a, Duration b) {
+  if (a == null)
+    return b;
+  if (b == null)
+    return a;
+  if (a > b)
+    return a;
+  return b;
+}
+
 /// A convenient accessor to frequently used finders.
 ///
 /// Examples:
@@ -142,7 +138,6 @@ class FlutterDriver {
     this._appIsolate, {
     bool printCommunication = false,
     bool logCommunicationToFile = true,
-    this.timeoutMultiplier = _kDefaultTimeoutMultiplier,
   }) : _printCommunication = printCommunication,
        _logCommunicationToFile = logCommunicationToFile,
        _driverId = _nextDriverId++;
@@ -159,41 +154,38 @@ class FlutterDriver {
   ///
   /// Resumes the application if it is currently paused (e.g. at a breakpoint).
   ///
-  /// [dartVmServiceUrl] is the URL to Dart observatory (a.k.a. VM service). If
+  /// `dartVmServiceUrl` is the URL to Dart observatory (a.k.a. VM service). If
   /// not specified, the URL specified by the `VM_SERVICE_URL` environment
   /// variable is used. One or the other must be specified.
   ///
-  /// [printCommunication] determines whether the command communication between
+  /// `printCommunication` determines whether the command communication between
   /// the test and the app should be printed to stdout.
   ///
-  /// [logCommunicationToFile] determines whether the command communication
+  /// `logCommunicationToFile` determines whether the command communication
   /// between the test and the app should be logged to `flutter_driver_commands.log`.
   ///
-  /// [FlutterDriver] multiplies all command timeouts by [timeoutMultiplier].
-  ///
-  /// [isolateNumber] (optional) determines the specific isolate to connect to.
+  /// `isolateNumber` determines the specific isolate to connect to.
   /// If this is left as `null`, will connect to the first isolate found
-  /// running on [dartVmServiceUrl].
-  ///
-  /// [isolateReadyTimeout] determines how long after we connect to the VM
-  /// service we will wait for the first isolate to become runnable. Explicitly
-  /// specified non-null values are not affected by [timeoutMultiplier].
-  ///
-  /// [fuchsiaModuleTarget] (optional) If running on a Fuchsia Device, either
-  /// this or the environment variable `FUCHSIA_MODULE_TARGET` must be set. This
-  /// field will be ignored if [isolateNumber] is set, as this is already
-  /// enough information to connect to an Isolate.
+  /// running on `dartVmServiceUrl`.
+  ///
+  /// `fuchsiaModuleTarget` specifies the pattern for determining which mod to
+  /// control. When running on a Fuchsia device, either this or the environment
+  /// variable `FUCHSIA_MODULE_TARGET` must be set (the environment variable is
+  /// treated as a substring pattern). This field will be ignored if
+  /// `isolateNumber` is set, as this is already enough information to connect
+  /// to an isolate.
+  ///
+  /// The return value is a future. This method never times out, though it may
+  /// fail (completing with an error). A timeout can be applied by the caller
+  /// using [Future.timeout] if necessary.
   static Future<FlutterDriver> connect({
     String dartVmServiceUrl,
     bool printCommunication = false,
     bool logCommunicationToFile = true,
-    double timeoutMultiplier = _kDefaultTimeoutMultiplier,
     int isolateNumber,
-    Duration isolateReadyTimeout,
     Pattern fuchsiaModuleTarget,
   }) async {
-    isolateReadyTimeout ??= _isolateLoadRunnableTimeout(timeoutMultiplier);
-    // If running on a Fuchsia device, connect to the first Isolate whose name
+    // If running on a Fuchsia device, connect to the first isolate whose name
     // matches FUCHSIA_MODULE_TARGET.
     //
     // If the user has already supplied an isolate number/URL to the Dart VM
@@ -204,16 +196,17 @@ class FlutterDriver {
       flutterDriverLog.listen(print);
       fuchsiaModuleTarget ??= Platform.environment['FUCHSIA_MODULE_TARGET'];
       if (fuchsiaModuleTarget == null) {
-        throw DriverError('No Fuchsia module target has been specified.\n'
-            'Please make sure to specify the FUCHSIA_MODULE_TARGET\n'
-            'environment variable.');
+        throw DriverError(
+          'No Fuchsia module target has been specified.\n'
+          'Please make sure to specify the FUCHSIA_MODULE_TARGET '
+          'environment variable.'
+        );
       }
       final fuchsia.FuchsiaRemoteConnection fuchsiaConnection =
           await FuchsiaCompat.connect();
       final List<fuchsia.IsolateRef> refs =
           await fuchsiaConnection.getMainIsolatesByPattern(fuchsiaModuleTarget);
       final fuchsia.IsolateRef ref = refs.first;
-      await Future<void>.delayed(_fuchsiaDriveDelay(timeoutMultiplier));
       isolateNumber = ref.number;
       dartVmServiceUrl = ref.dartVm.uri.toString();
       await fuchsiaConnection.stop();
@@ -224,14 +217,14 @@ class FlutterDriver {
 
     if (dartVmServiceUrl == null) {
       throw DriverError(
-          'Could not determine URL to connect to application.\n'
-          'Either the VM_SERVICE_URL environment variable should be set, or an explicit\n'
-          'URL should be provided to the FlutterDriver.connect() method.');
+        'Could not determine URL to connect to application.\n'
+        'Either the VM_SERVICE_URL environment variable should be set, or an explicit '
+        'URL should be provided to the FlutterDriver.connect() method.'
+      );
     }
 
     // Connect to Dart VM services
     _log.info('Connecting to Flutter application at $dartVmServiceUrl');
-    connectionTimeoutMultiplier = timeoutMultiplier;
     final VMServiceClientConnection connection =
         await vmServiceConnectFunction(dartVmServiceUrl);
     final VMServiceClient client = connection.client;
@@ -242,12 +235,7 @@ class FlutterDriver {
                    (VMIsolateRef isolate) => isolate.number == isolateNumber);
     _log.trace('Isolate found with number: ${isolateRef.number}');
 
-    VMIsolate isolate = await isolateRef
-        .loadRunnable()
-        .timeout(isolateReadyTimeout, onTimeout: () {
-      throw TimeoutException(
-          'Timeout while waiting for the isolate to become runnable');
-    });
+    VMIsolate isolate = await isolateRef.loadRunnable();
 
     // TODO(yjbanov): vm_service_client does not support "None" pause event yet.
     // It is currently reported as null, but we cannot rely on it because
@@ -262,7 +250,6 @@ class FlutterDriver {
         isolate.pauseEvent is! VMPauseExceptionEvent &&
         isolate.pauseEvent is! VMPauseInterruptedEvent &&
         isolate.pauseEvent is! VMResumeEvent) {
-      await Future<void>.delayed(_shortTimeout(timeoutMultiplier) ~/ 10);
       isolate = await isolateRef.loadRunnable();
     }
 
@@ -270,7 +257,6 @@ class FlutterDriver {
       client, connection.peer, isolate,
       printCommunication: printCommunication,
       logCommunicationToFile: logCommunicationToFile,
-      timeoutMultiplier: timeoutMultiplier,
     );
 
     // Attempts to resume the isolate, but does not crash if it fails because
@@ -323,23 +309,21 @@ class FlutterDriver {
       // option, then the VM service extension is not registered yet. Wait for
       // it to be registered.
       await enableIsolateStreams();
-      final Future<dynamic> whenServiceExtensionReady = waitForServiceExtension();
+      final Future<String> whenServiceExtensionReady = waitForServiceExtension();
       final Future<dynamic> whenResumed = resumeLeniently();
       await whenResumed;
 
-      try {
-        _log.trace('Waiting for service extension');
-        // We will never receive the extension event if the user does not
-        // register it. If that happens time out.
-        await whenServiceExtensionReady.timeout(_longTimeout(timeoutMultiplier) * 2);
-      } on TimeoutException catch (_) {
-        throw DriverError(
-          'Timed out waiting for Flutter Driver extension to become available. '
-          'Ensure your test app (often: lib/main.dart) imports '
-          '"package:flutter_driver/driver_extension.dart" and '
-          'calls enableFlutterDriverExtension() as the first call in main().'
-        );
-      }
+      _log.trace('Waiting for service extension');
+      // We will never receive the extension event if the user does not
+      // register it. If that happens, show a message but continue waiting.
+      await _warnIfSlow<String>(
+        future: whenServiceExtensionReady,
+        timeout: _kUnusuallyLongTimeout,
+        message: 'Flutter Driver extension is taking a long time to become available. '
+                 'Ensure your test app (often "lib/main.dart") imports '
+                 '"package:flutter_driver/driver_extension.dart" and '
+                 'calls enableFlutterDriverExtension() as the first call in main().'
+      );
     } else if (isolate.pauseEvent is VMPauseExitEvent ||
                isolate.pauseEvent is VMPauseBreakpointEvent ||
                isolate.pauseEvent is VMPauseExceptionEvent ||
@@ -372,7 +356,7 @@ class FlutterDriver {
           'registered.'
         );
         await enableIsolateStreams();
-        await waitForServiceExtension().timeout(_longTimeout(timeoutMultiplier) * 2);
+        await waitForServiceExtension();
         return driver.checkHealth();
       }
     }
@@ -405,29 +389,21 @@ class FlutterDriver {
   /// Whether to log communication between host and app to `flutter_driver_commands.log`.
   final bool _logCommunicationToFile;
 
-  /// [FlutterDriver] multiplies all command timeouts by this number.
-  ///
-  /// The right amount of time a driver command should be given to complete
-  /// depends on various environmental factors, such as the speed of the
-  /// device or the emulator, connection speed and latency, and others. Use
-  /// this multiplier to tailor the timeouts to your environment.
-  final double timeoutMultiplier;
-
   Future<Map<String, dynamic>> _sendCommand(Command command) async {
     Map<String, dynamic> response;
     try {
       final Map<String, String> serialized = command.serialize();
       _logCommunication('>>> $serialized');
-      response = await _appIsolate
-          .invokeExtension(_flutterExtensionMethodName, serialized)
-          .timeout(command.timeout + _rpcGraceTime(timeoutMultiplier));
-      _logCommunication('<<< $response');
-    } on TimeoutException catch (error, stackTrace) {
-      throw DriverError(
-        'Failed to fulfill ${command.runtimeType}: Flutter application not responding',
-        error,
-        stackTrace,
+      final Future<Map<String, dynamic>> future = _appIsolate.invokeExtension(
+        _flutterExtensionMethodName,
+        serialized,
+      ).then<Map<String, dynamic>>((Object value) => value);
+      response = await _warnIfSlow<Map<String, dynamic>>(
+        future: future,
+        timeout: _maxDuration(command.timeout, _kUnusuallyLongTimeout),
+        message: '${command.kind} message is taking a long time to complete...',
       );
+      _logCommunication('<<< $response');
     } catch (error, stackTrace) {
       throw DriverError(
         'Failed to fulfill ${command.runtimeType} due to remote error',
@@ -452,31 +428,26 @@ class FlutterDriver {
 
   /// Checks the status of the Flutter Driver extension.
   Future<Health> checkHealth({Duration timeout}) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     return Health.fromJson(await _sendCommand(GetHealth(timeout: timeout)));
   }
 
   /// Returns a dump of the render tree.
   Future<RenderTree> getRenderTree({Duration timeout}) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     return RenderTree.fromJson(await _sendCommand(GetRenderTree(timeout: timeout)));
   }
 
   /// Taps at the center of the widget located by [finder].
   Future<void> tap(SerializableFinder finder, {Duration timeout}) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(Tap(finder, timeout: timeout));
   }
 
   /// Waits until [finder] locates the target.
   Future<void> waitFor(SerializableFinder finder, {Duration timeout}) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(WaitFor(finder, timeout: timeout));
   }
 
   /// Waits until [finder] can no longer locate the target.
   Future<void> waitForAbsent(SerializableFinder finder, {Duration timeout}) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(WaitForAbsent(finder, timeout: timeout));
   }
 
@@ -485,7 +456,6 @@ class FlutterDriver {
   /// Use this method when you need to wait for the moment when the application
   /// becomes "stable", for example, prior to taking a [screenshot].
   Future<void> waitUntilNoTransientCallbacks({Duration timeout}) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(WaitUntilNoTransientCallbacks(timeout: timeout));
   }
 
@@ -503,7 +473,6 @@ class FlutterDriver {
   /// The move events are generated at a given [frequency] in Hz (or events per
   /// second). It defaults to 60Hz.
   Future<void> scroll(SerializableFinder finder, double dx, double dy, Duration duration, { int frequency = 60, Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(Scroll(finder, dx, dy, duration, frequency, timeout: timeout));
   }
 
@@ -515,7 +484,6 @@ class FlutterDriver {
   /// then this method may fail because [finder] doesn't actually exist.
   /// The [scrollUntilVisible] method can be used in this case.
   Future<void> scrollIntoView(SerializableFinder finder, { double alignment = 0.0, Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(ScrollIntoView(finder, alignment: alignment, timeout: timeout));
   }
 
@@ -540,12 +508,12 @@ class FlutterDriver {
   /// for [dyScroll].
   ///
   /// The [timeout] value should be long enough to accommodate as many scrolls
-  /// as needed to bring an item into view. The default is 10 seconds.
+  /// as needed to bring an item into view. The default is to not time out.
   Future<void> scrollUntilVisible(SerializableFinder scrollable, SerializableFinder item, {
     double alignment = 0.0,
     double dxScroll = 0.0,
     double dyScroll = 0.0,
-    Duration timeout = const Duration(seconds: 10),
+    Duration timeout,
   }) async {
     assert(scrollable != null);
     assert(item != null);
@@ -553,7 +521,6 @@ class FlutterDriver {
     assert(dxScroll != null);
     assert(dyScroll != null);
     assert(dxScroll != 0.0 || dyScroll != 0.0);
-    assert(timeout != null);
 
     // Kick off an (unawaited) waitFor that will complete when the item we're
     // looking for finally scrolls onscreen. We add an initial pause to give it
@@ -572,7 +539,6 @@ class FlutterDriver {
 
   /// Returns the text in the `Text` widget located by [finder].
   Future<String> getText(SerializableFinder finder, { Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     return GetTextResult.fromJson(await _sendCommand(GetText(finder, timeout: timeout))).text;
   }
 
@@ -609,7 +575,6 @@ class FlutterDriver {
   /// });
   /// ```
   Future<void> enterText(String text, { Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(EnterText(text, timeout: timeout));
   }
 
@@ -628,7 +593,6 @@ class FlutterDriver {
   /// channel will be mocked out.
   Future<void> setTextEntryEmulation({ @required bool enabled, Duration timeout }) async {
     assert(enabled != null);
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(SetTextEntryEmulation(enabled, timeout: timeout));
   }
 
@@ -639,7 +603,6 @@ class FlutterDriver {
   /// callback in [enableFlutterDriverExtension] that can successfully handle
   /// these requests.
   Future<String> requestData(String message, { Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     return RequestDataResult.fromJson(await _sendCommand(RequestData(message, timeout: timeout))).message;
   }
 
@@ -648,7 +611,6 @@ class FlutterDriver {
   /// Returns true when the call actually changed the state from on to off or
   /// vice versa.
   Future<bool> setSemantics(bool enabled, { Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     final SetSemanticsResult result = SetSemanticsResult.fromJson(await _sendCommand(SetSemantics(enabled, timeout: timeout)));
     return result.changedState;
   }
@@ -662,16 +624,15 @@ class FlutterDriver {
   /// Semantics must be enabled to use this method, either using a platform
   /// specific shell command or [setSemantics].
   Future<int> getSemanticsId(SerializableFinder finder, { Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     final Map<String, dynamic> jsonResponse = await _sendCommand(GetSemanticsId(finder, timeout: timeout));
     final GetSemanticsIdResult result = GetSemanticsIdResult.fromJson(jsonResponse);
     return result.id;
   }
 
-  /// Take a screenshot.  The image will be returned as a PNG.
-  Future<List<int>> screenshot({ Duration timeout }) async {
-    timeout ??= _longTimeout(timeoutMultiplier);
-
+  /// Take a screenshot.
+  ///
+  /// The image will be returned as a PNG.
+  Future<List<int>> screenshot() async {
     // HACK: this artificial delay here is to deal with a race between the
     //       driver script and the GPU thread. The issue is that driver API
     //       synchronizes with the framework based on transient callbacks, which
@@ -679,7 +640,7 @@ class FlutterDriver {
     //       in ASCII art:
     //
     //       -------------------------------------------------------------------
-    //       Before this change:
+    //       Without this delay:
     //       -------------------------------------------------------------------
     //       UI    : <-- build -->
     //       GPU   :               <-- rasterize -->
@@ -690,12 +651,13 @@ class FlutterDriver {
     //       action taken, such as a `tap()`, and the subsequent call to
     //       `screenshot()`. The gap is random because it is determined by the
     //       unpredictable network communication between the driver process and
-    //       the application. If this gap is too short, the screenshot is taken
-    //       before the GPU thread is done rasterizing the frame, so the
-    //       screenshot of the previous frame is taken, which is wrong.
+    //       the application. If this gap is too short, which it typically will
+    //       be, the screenshot is taken before the GPU thread is done
+    //       rasterizing the frame, so the screenshot of the previous frame is
+    //       taken, which is wrong.
     //
     //       -------------------------------------------------------------------
-    //       After this change:
+    //       With this delay, if we're lucky:
     //       -------------------------------------------------------------------
     //       UI    : <-- build -->
     //       GPU   :               <-- rasterize -->
@@ -705,16 +667,28 @@ class FlutterDriver {
     //       The two-second gap should be long enough for the GPU thread to
     //       finish rasterizing the frame, but not longer than necessary to keep
     //       driver tests as fast a possible.
+    //
+    //       -------------------------------------------------------------------
+    //       With this delay, if we're not lucky:
+    //       -------------------------------------------------------------------
+    //       UI    : <-- build -->
+    //       GPU   :               <-- rasterize randomly slow today -->
+    //       Gap   :              |    2 seconds or more   |
+    //       Driver:                                        <-- screenshot -->
+    //
+    //       In practice, sometimes the device gets really busy for a while and
+    //       even two seconds isn't enough, which means that this is still racy
+    //       and a source of flakes.
     await Future<void>.delayed(const Duration(seconds: 2));
 
-    final Map<String, dynamic> result = await _peer.sendRequest('_flutter.screenshot').timeout(timeout);
+    final Map<String, dynamic> result = await _peer.sendRequest('_flutter.screenshot');
     return base64.decode(result['screenshot']);
   }
 
   /// Returns the Flags set in the Dart VM as JSON.
   ///
-  /// See the complete documentation for `getFlagList` Dart VM service method
-  /// [here][getFlagList].
+  /// See the complete documentation for [the `getFlagList` Dart VM service
+  /// method][getFlagList].
   ///
   /// Example return value:
   ///
@@ -730,23 +704,30 @@ class FlutterDriver {
   ///     ]
   ///
   /// [getFlagList]: https://github.com/dart-lang/sdk/blob/master/runtime/vm/service/service.md#getflaglist
-  Future<List<Map<String, dynamic>>> getVmFlags({ Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
-    final Map<String, dynamic> result = await _peer.sendRequest('getFlagList').timeout(timeout);
+  Future<List<Map<String, dynamic>>> getVmFlags() async {
+    final Map<String, dynamic> result = await _peer.sendRequest('getFlagList');
     return result['flags'];
   }
 
   /// Starts recording performance traces.
+  ///
+  /// The `timeout` argument causes a warning to be displayed to the user if the
+  /// operation exceeds the specified timeout; it does not actually cancel the
+  /// operation.
   Future<void> startTracing({
     List<TimelineStream> streams = _defaultStreams,
-    Duration timeout,
+    Duration timeout = _kUnusuallyLongTimeout,
   }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     assert(streams != null && streams.isNotEmpty);
+    assert(timeout != null);
     try {
-      await _peer.sendRequest(_setVMTimelineFlagsMethodName, <String, String>{
-        'recordedStreams': _timelineStreamsToString(streams)
-      }).timeout(timeout);
+      await _warnIfSlow<void>(
+        future: _peer.sendRequest(_setVMTimelineFlagsMethodName, <String, String>{
+          'recordedStreams': _timelineStreamsToString(streams)
+        }),
+        timeout: timeout,
+        message: 'VM is taking an unusually long time to respond to being told to start tracing...',
+      );
     } catch (error, stackTrace) {
       throw DriverError(
         'Failed to start tracing due to remote error',
@@ -757,12 +738,20 @@ class FlutterDriver {
   }
 
   /// Stops recording performance traces and downloads the timeline.
-  Future<Timeline> stopTracingAndDownloadTimeline({ Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
+  ///
+  /// The `timeout` argument causes a warning to be displayed to the user if the
+  /// operation exceeds the specified timeout; it does not actually cancel the
+  /// operation.
+  Future<Timeline> stopTracingAndDownloadTimeline({
+    Duration timeout = _kUnusuallyLongTimeout,
+  }) async {
+    assert(timeout != null);
     try {
-      await _peer
-          .sendRequest(_setVMTimelineFlagsMethodName, <String, String>{'recordedStreams': '[]'})
-          .timeout(timeout);
+      await _warnIfSlow<void>(
+        future: _peer.sendRequest(_setVMTimelineFlagsMethodName, <String, String>{'recordedStreams': '[]'}),
+        timeout: timeout,
+        message: 'VM is taking an unusually long time to respond to being told to stop tracing...',
+      );
       return Timeline.fromJson(await _peer.sendRequest(_getVMTimelineMethodName));
     } catch (error, stackTrace) {
       throw DriverError(
@@ -801,12 +790,20 @@ class FlutterDriver {
   }
 
   /// Clears all timeline events recorded up until now.
-  Future<void> clearTimeline({ Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
+  ///
+  /// The `timeout` argument causes a warning to be displayed to the user if the
+  /// operation exceeds the specified timeout; it does not actually cancel the
+  /// operation.
+  Future<void> clearTimeline({
+    Duration timeout = _kUnusuallyLongTimeout
+  }) async {
+    assert(timeout != null);
     try {
-      await _peer
-          .sendRequest(_clearVMTimelineMethodName, <String, String>{})
-          .timeout(timeout);
+      await _warnIfSlow<void>(
+        future: _peer.sendRequest(_clearVMTimelineMethodName, <String, String>{}),
+        timeout: timeout,
+        message: 'VM is taking an unusually long time to respond to being told to clear its timeline buffer...',
+      );
     } catch (error, stackTrace) {
       throw DriverError(
         'Failed to clear event timeline due to remote error',
@@ -833,7 +830,6 @@ class FlutterDriver {
   /// ensure that no action is performed while the app is undergoing a
   /// transition to avoid flakiness.
   Future<T> runUnsynchronized<T>(Future<T> action(), { Duration timeout }) async {
-    timeout ??= _shortTimeout(timeoutMultiplier);
     await _sendCommand(SetFrameSync(false, timeout: timeout));
     T result;
     try {
@@ -893,11 +889,6 @@ typedef VMServiceConnectFunction = Future<VMServiceClientConnection> Function(St
 ///
 /// Overwrite this function if you require a custom method for connecting to
 /// the VM service.
-///
-/// See also:
-///
-///  * [connectionTimeoutMultiplier], which controls the timeouts while
-///    establishing a connection using the default connection function.
 VMServiceConnectFunction vmServiceConnectFunction = _waitAndConnect;
 
 /// Restores [vmServiceConnectFunction] to its default value.
@@ -907,44 +898,30 @@ void restoreVmServiceConnectFunction() {
 
 /// Waits for a real Dart VM service to become available, then connects using
 /// the [VMServiceClient].
-///
-/// Times out after 30 seconds.
 Future<VMServiceClientConnection> _waitAndConnect(String url) async {
-  final Stopwatch timer = Stopwatch()..start();
-
-  Future<VMServiceClientConnection> attemptConnection() async {
-    Uri uri = Uri.parse(url);
-    if (uri.scheme == 'http')
-      uri = uri.replace(scheme: 'ws', path: '/ws');
-
+  Uri uri = Uri.parse(url);
+  if (uri.scheme == 'http')
+    uri = uri.replace(scheme: 'ws', path: '/ws');
+  int attempts = 0;
+  while (true) {
     WebSocket ws1;
     WebSocket ws2;
     try {
-      ws1 = await WebSocket.connect(uri.toString()).timeout(_shortTimeout(connectionTimeoutMultiplier));
-      ws2 = await WebSocket.connect(uri.toString()).timeout(_shortTimeout(connectionTimeoutMultiplier));
+      ws1 = await WebSocket.connect(uri.toString());
+      ws2 = await WebSocket.connect(uri.toString());
       return VMServiceClientConnection(
         VMServiceClient(IOWebSocketChannel(ws1).cast()),
-        rpc.Peer(IOWebSocketChannel(ws2).cast())..listen()
+        rpc.Peer(IOWebSocketChannel(ws2).cast())..listen(),
       );
     } catch (e) {
       await ws1?.close();
       await ws2?.close();
-
-      if (timer.elapsed < _longTimeout(connectionTimeoutMultiplier) * 2) {
-        _log.info('Waiting for application to start');
-        await Future<void>.delayed(_pauseBetweenReconnectAttempts(connectionTimeoutMultiplier));
-        return attemptConnection();
-      } else {
-        _log.critical(
-          'Application has not started in 30 seconds. '
-          'Giving up.'
-        );
-        rethrow;
-      }
+      if (attempts > 5)
+        _log.warning('It is taking an unusually long time to connect to the VM...');
+      attempts += 1;
+      await Future<void>.delayed(_kPauseBetweenReconnectAttempts);
     }
   }
-
-  return attemptConnection();
 }
 
 /// Provides convenient accessors to frequently used finders.

packages/flutter_driver/lib/src/extension/extension.dart

@@ -177,7 +177,10 @@ class FlutterDriverExtension {
       if (commandHandler == null || commandDeserializer == null)
         throw 'Extension $_extensionMethod does not support command $commandKind';
       final Command command = commandDeserializer(params);
-      final Result response = await commandHandler(command).timeout(command.timeout);
+      Future<Result> responseFuture = commandHandler(command);
+      if (command.timeout != null)
+        responseFuture = responseFuture.timeout(command.timeout);
+      final Result response = await responseFuture;
       return _makeResponse(response?.toJson());
     } on TimeoutException catch (error, stackTrace) {
       final String msg = 'Timeout while executing $commandKind: $error\n$stackTrace';

packages/flutter_driver/test/flutter_driver_test.dart

@@ -11,13 +11,13 @@ import 'package:flutter_driver/src/driver/timeline.dart';
 import 'package:json_rpc_2/json_rpc_2.dart' as rpc;
 import 'package:mockito/mockito.dart';
 import 'package:vm_service_client/vm_service_client.dart';
+import 'package:quiver/testing/async.dart';
 
 import 'common.dart';
 
 /// Magical timeout value that's different from the default.
 const Duration _kTestTimeout = Duration(milliseconds: 1234);
 const String _kSerializedTestTimeout = '1234';
-const Duration _kDefaultCommandTimeout = Duration(seconds: 5);
 
 void main() {
   group('FlutterDriver.connect', () {
@@ -358,17 +358,19 @@ void main() {
 
     group('sendCommand error conditions', () {
       test('local timeout', () async {
+        final List<String> log = <String>[];
+        final StreamSubscription<LogRecord> logSub = flutterDriverLog.listen((LogRecord s) => log.add(s.toString()));
         when(mockIsolate.invokeExtension(any, any)).thenAnswer((Invocation i) {
-          // completer never competed to trigger timeout
+          // completer never completed to trigger timeout
           return Completer<Map<String, dynamic>>().future;
         });
-        try {
-          await driver.waitFor(find.byTooltip('foo'), timeout: const Duration(milliseconds: 100));
-          fail('expected an exception');
-        } catch (error) {
-          expect(error is DriverError, isTrue);
-          expect(error.message, 'Failed to fulfill WaitFor: Flutter application not responding');
-        }
+        FakeAsync().run((FakeAsync time) {
+          driver.waitFor(find.byTooltip('foo'));
+          expect(log, <String>[]);
+          time.elapse(const Duration(hours: 1));
+        });
+        expect(log, <String>['[warning] FlutterDriver: waitFor message is taking a long time to complete...']);
+        await logSub.cancel();
       });
 
       test('remote error', () async {
@@ -389,7 +391,6 @@ void main() {
   });
 
   group('FlutterDriver with custom timeout', () {
-    const double kTestMultiplier = 3.0;
     MockVMServiceClient mockClient;
     MockPeer mockPeer;
     MockIsolate mockIsolate;
@@ -399,21 +400,20 @@ void main() {
       mockClient = MockVMServiceClient();
       mockPeer = MockPeer();
       mockIsolate = MockIsolate();
-      driver = FlutterDriver.connectedTo(mockClient, mockPeer, mockIsolate, timeoutMultiplier: kTestMultiplier);
+      driver = FlutterDriver.connectedTo(mockClient, mockPeer, mockIsolate);
     });
 
-    test('multiplies the timeout', () async {
+    test('GetHealth has no default timeout', () async {
       when(mockIsolate.invokeExtension(any, any)).thenAnswer((Invocation i) {
         expect(i.positionalArguments[1], <String, String>{
           'command': 'get_health',
-          'timeout': '${(_kDefaultCommandTimeout * kTestMultiplier).inMilliseconds}',
         });
         return makeMockResponse(<String, dynamic>{'status': 'ok'});
       });
       await driver.checkHealth();
     });
 
-    test('does not multiply explicit timeouts', () async {
+    test('does not interfere with explicit timeouts', () async {
       when(mockIsolate.invokeExtension(any, any)).thenAnswer((Invocation i) {
         expect(i.positionalArguments[1], <String, String>{
           'command': 'get_health',

packages/flutter_tools/lib/src/android/android_device.dart

@@ -88,15 +88,13 @@ class AndroidDevice extends Device {
           propCommand,
           stdoutEncoding: latin1,
           stderrEncoding: latin1,
-        ).timeout(const Duration(seconds: 5));
+        );
         if (result.exitCode == 0) {
           _properties = parseAdbDeviceProperties(result.stdout);
         } else {
           printError('Error retrieving device properties for $name:');
           printError(result.stderr);
         }
-      } on TimeoutException catch (_) {
-        throwToolExit('adb not responding');
       } on ProcessException catch (error) {
         printError('Error retrieving device properties for $name: $error');
       }
@@ -279,7 +277,7 @@ class AndroidDevice extends Device {
     if (!await _checkForSupportedAdbVersion() || !await _checkForSupportedAndroidVersion())
       return false;
 
-    final Status status = logger.startProgress('Installing ${fs.path.relative(apk.file.path)}...', expectSlowOperation: true);
+    final Status status = logger.startProgress('Installing ${fs.path.relative(apk.file.path)}...', timeout: kSlowOperation);
     final RunResult installResult = await runAsync(adbCommandForDevice(<String>['install', '-t', '-r', apk.file.path]));
     status.stop();
     // Some versions of adb exit with exit code 0 even on failure :(

packages/flutter_tools/lib/src/android/android_emulator.dart

@@ -51,9 +51,10 @@ class AndroidEmulator extends Emulator {
                 throw '${runResult.stdout}\n${runResult.stderr}'.trimRight();
               }
             });
-    // emulator continues running on a successful launch so if we
-    // haven't quit within 3 seconds we assume that's a success and just
-    // return.
+    // The emulator continues running on a successful launch, so if it hasn't
+    // quit within 3 seconds we assume that's a success and just return. This
+    // means that on a slow machine, a failure that takes more than three
+    // seconds won't be recognized as such... :-/
     return Future.any<void>(<Future<void>>[
       launchResult,
       Future<void>.delayed(const Duration(seconds: 3))

packages/flutter_tools/lib/src/android/android_workflow.dart

@@ -50,32 +50,41 @@ class AndroidWorkflow implements Workflow {
 class AndroidValidator extends DoctorValidator {
   AndroidValidator(): super('Android toolchain - develop for Android devices',);
 
+  @override
+  String get slowWarning => '${_task ?? 'This'} is taking a long time...';
+  String _task;
+
   /// Returns false if we cannot determine the Java version or if the version
   /// is not compatible.
   Future<bool> _checkJavaVersion(String javaBinary, List<ValidationMessage> messages) async {
-    if (!processManager.canRun(javaBinary)) {
-      messages.add(ValidationMessage.error(userMessages.androidCantRunJavaBinary(javaBinary)));
-      return false;
-    }
-    String javaVersion;
+    _task = 'Checking Java status';
     try {
-      printTrace('java -version');
-      final ProcessResult result = await processManager.run(<String>[javaBinary, '-version']);
-      if (result.exitCode == 0) {
-        final List<String> versionLines = result.stderr.split('\n');
-        javaVersion = versionLines.length >= 2 ? versionLines[1] : versionLines[0];
+      if (!processManager.canRun(javaBinary)) {
+        messages.add(ValidationMessage.error(userMessages.androidCantRunJavaBinary(javaBinary)));
+        return false;
       }
-    } catch (error) {
-      printTrace(error.toString());
-    }
-    if (javaVersion == null) {
-      // Could not determine the java version.
-      messages.add(ValidationMessage.error(userMessages.androidUnknownJavaVersion));
-      return false;
+      String javaVersion;
+      try {
+        printTrace('java -version');
+        final ProcessResult result = await processManager.run(<String>[javaBinary, '-version']);
+        if (result.exitCode == 0) {
+          final List<String> versionLines = result.stderr.split('\n');
+          javaVersion = versionLines.length >= 2 ? versionLines[1] : versionLines[0];
+        }
+      } catch (error) {
+        printTrace(error.toString());
+      }
+      if (javaVersion == null) {
+        // Could not determine the java version.
+        messages.add(ValidationMessage.error(userMessages.androidUnknownJavaVersion));
+        return false;
+      }
+      messages.add(ValidationMessage(userMessages.androidJavaVersion(javaVersion)));
+      // TODO(johnmccutchan): Validate version.
+      return true;
+    } finally {
+      _task = null;
     }
-    messages.add(ValidationMessage(userMessages.androidJavaVersion(javaVersion)));
-    // TODO(johnmccutchan): Validate version.
-    return true;
   }
 
   @override
@@ -149,6 +158,9 @@ class AndroidValidator extends DoctorValidator {
 class AndroidLicenseValidator extends DoctorValidator {
   AndroidLicenseValidator(): super('Android license subvalidator',);
 
+  @override
+  String get slowWarning => 'Checking Android licenses is taking an unexpectedly long time...';
+
   @override
   Future<ValidationResult> validate() async {
     final List<ValidationMessage> messages = <ValidationMessage>[];
@@ -208,10 +220,8 @@ class AndroidLicenseValidator extends DoctorValidator {
   Future<LicensesAccepted> get licensesAccepted async {
     LicensesAccepted status;
 
-    void _onLine(String line) {
-      if (status == null && licenseAccepted.hasMatch(line)) {
-        status = LicensesAccepted.all;
-      } else if (licenseCounts.hasMatch(line)) {
+    void _handleLine(String line) {
+      if (licenseCounts.hasMatch(line)) {
         final Match match = licenseCounts.firstMatch(line);
         if (match.group(1) != match.group(2)) {
           status = LicensesAccepted.some;
@@ -219,9 +229,12 @@ class AndroidLicenseValidator extends DoctorValidator {
           status = LicensesAccepted.none;
         }
       } else if (licenseNotAccepted.hasMatch(line)) {
-        // In case the format changes, a more general match will keep doctor
-        // mostly working.
+        // The licenseNotAccepted pattern is trying to match the same line as
+        // licenseCounts, but is more general. In case the format changes, a
+        // more general match may keep doctor mostly working.
         status = LicensesAccepted.none;
+      } else if (licenseAccepted.hasMatch(line)) {
+        status ??= LicensesAccepted.all;
       }
     }
 
@@ -235,19 +248,14 @@ class AndroidLicenseValidator extends DoctorValidator {
     final Future<void> output = process.stdout
       .transform<String>(const Utf8Decoder(allowMalformed: true))
       .transform<String>(const LineSplitter())
-      .listen(_onLine)
+      .listen(_handleLine)
       .asFuture<void>(null);
     final Future<void> errors = process.stderr
       .transform<String>(const Utf8Decoder(allowMalformed: true))
       .transform<String>(const LineSplitter())
-      .listen(_onLine)
+      .listen(_handleLine)
       .asFuture<void>(null);
-    try {
-      await Future.wait<void>(<Future<void>>[output, errors]).timeout(const Duration(seconds: 30));
-    } catch (TimeoutException) {
-      printTrace(userMessages.androidLicensesTimeout(androidSdk.sdkManagerPath));
-      processManager.killPid(process.pid);
-    }
+    await Future.wait<void>(<Future<void>>[output, errors]);
     return status ?? LicensesAccepted.unknown;
   }
 
@@ -261,9 +269,10 @@ class AndroidLicenseValidator extends DoctorValidator {
     _ensureCanRunSdkManager();
 
     final Version sdkManagerVersion = Version.parse(androidSdk.sdkManagerVersion);
-    if (sdkManagerVersion == null || sdkManagerVersion.major < 26)
+    if (sdkManagerVersion == null || sdkManagerVersion.major < 26) {
       // SDK manager is found, but needs to be updated.
       throwToolExit(userMessages.androidSdkOutdated(androidSdk.sdkManagerPath));
+    }
 
     final Process process = await runCommand(
       <String>[androidSdk.sdkManagerPath, '--licenses'],

packages/flutter_tools/lib/src/android/gradle.dart

@@ -97,7 +97,7 @@ Future<GradleProject> _readGradleProject() async {
   final FlutterProject flutterProject = await FlutterProject.current();
   final String gradle = await _ensureGradle(flutterProject);
   updateLocalProperties(project: flutterProject);
-  final Status status = logger.startProgress('Resolving dependencies...', expectSlowOperation: true);
+  final Status status = logger.startProgress('Resolving dependencies...', timeout: kSlowOperation);
   GradleProject project;
   try {
     final RunResult propertiesRunResult = await runCheckedAsync(
@@ -175,7 +175,7 @@ Future<String> _ensureGradle(FlutterProject project) async {
 // of validating the Gradle executable. This may take several seconds.
 Future<String> _initializeGradle(FlutterProject project) async {
   final Directory android = project.android.hostAppGradleRoot;
-  final Status status = logger.startProgress('Initializing gradle...', expectSlowOperation: true);
+  final Status status = logger.startProgress('Initializing gradle...', timeout: kSlowOperation);
   String gradle = _locateGradlewExecutable(android);
   if (gradle == null) {
     injectGradleWrapper(android);
@@ -314,8 +314,8 @@ Future<void> buildGradleProject({
 Future<void> _buildGradleProjectV1(FlutterProject project, String gradle) async {
   // Run 'gradlew build'.
   final Status status = logger.startProgress(
-    "Running 'gradlew build'...",
-    expectSlowOperation: true,
+    'Running \'gradlew build\'...',
+    timeout: kSlowOperation,
     multilineOutput: true,
   );
   final int exitCode = await runCommandAndStreamOutput(
@@ -365,8 +365,8 @@ Future<void> _buildGradleProjectV2(
     }
   }
   final Status status = logger.startProgress(
-    "Gradle task '$assembleTask'...",
-    expectSlowOperation: true,
+    'Running Gradle task \'$assembleTask\'...',
+    timeout: kSlowOperation,
     multilineOutput: true,
   );
   final String gradlePath = fs.file(gradle).absolute.path;

packages/flutter_tools/lib/src/base/context.dart

@@ -107,7 +107,7 @@ class AppContext {
 
   /// Gets the value associated with the specified [type], or `null` if no
   /// such value has been associated.
-  dynamic operator [](Type type) {
+  Object operator [](Type type) {
     dynamic value = _generateIfNecessary(type, _overrides);
     if (value == null && _parent != null)
       value = _parent[type];

packages/flutter_tools/lib/src/base/file_system.dart

@@ -36,9 +36,7 @@ RecordingFileSystem getRecordingFileSystem(String location) {
   final RecordingFileSystem fileSystem = RecordingFileSystem(
       delegate: _kLocalFs, destination: dir);
   addShutdownHook(() async {
-    await fileSystem.recording.flush(
-      pendingResultTimeout: const Duration(seconds: 5),
-    );
+    await fileSystem.recording.flush();
   }, ShutdownStage.SERIALIZE_RECORDING);
   return fileSystem;
 }

packages/flutter_tools/lib/src/base/io.dart

@@ -162,10 +162,7 @@ class Stdio {
   bool get supportsAnsiEscapes => hasTerminal ? io.stdout.supportsAnsiEscapes : false;
 }
 
-io.IOSink get stderr => context[Stdio].stderr;
-
-Stream<List<int>> get stdin => context[Stdio].stdin;
-
-io.IOSink get stdout => context[Stdio].stdout;
-
 Stdio get stdio => context[Stdio];
+io.IOSink get stdout => stdio.stdout;
+Stream<List<int>> get stdin => stdio.stdin;
+io.IOSink get stderr => stdio.stderr;

packages/flutter_tools/lib/src/base/logger.dart

@@ -12,6 +12,8 @@ import 'terminal.dart';
 import 'utils.dart';
 
 const int kDefaultStatusPadding = 59;
+const Duration kFastOperation = Duration(seconds: 2);
+const Duration kSlowOperation = Duration(minutes: 2);
 
 typedef VoidCallback = void Function();
 
@@ -24,24 +26,30 @@ abstract class Logger {
 
   bool get hasTerminal => stdio.hasTerminal;
 
-  /// Display an error [message] to the user. Commands should use this if they
+  /// Display an error `message` to the user. Commands should use this if they
   /// fail in some way.
   ///
-  /// The [message] argument is printed to the stderr in red by default.
-  /// The [stackTrace] argument is the stack trace that will be printed if
+  /// The `message` argument is printed to the stderr in red by default.
+  ///
+  /// The `stackTrace` argument is the stack trace that will be printed if
   /// supplied.
-  /// The [emphasis] argument will cause the output message be printed in bold text.
-  /// The [color] argument will print the message in the supplied color instead
+  ///
+  /// The `emphasis` argument will cause the output message be printed in bold text.
+  ///
+  /// The `color` argument will print the message in the supplied color instead
   /// of the default of red. Colors will not be printed if the output terminal
   /// doesn't support them.
-  /// The [indent] argument specifies the number of spaces to indent the overall
+  ///
+  /// The `indent` argument specifies the number of spaces to indent the overall
   /// message. If wrapping is enabled in [outputPreferences], then the wrapped
   /// lines will be indented as well.
-  /// If [hangingIndent] is specified, then any wrapped lines will be indented
+  ///
+  /// If `hangingIndent` is specified, then any wrapped lines will be indented
   /// by this much more than the first line, if wrapping is enabled in
   /// [outputPreferences].
-  /// If [wrap] is specified, then it overrides the
-  /// [outputPreferences.wrapText] setting.
+  ///
+  /// If `wrap` is specified, then it overrides the
+  /// `outputPreferences.wrapText` setting.
   void printError(
     String message, {
     StackTrace stackTrace,
@@ -55,24 +63,31 @@ abstract class Logger {
   /// Display normal output of the command. This should be used for things like
   /// progress messages, success messages, or just normal command output.
   ///
-  /// The [message] argument is printed to the stderr in red by default.
-  /// The [stackTrace] argument is the stack trace that will be printed if
+  /// The `message` argument is printed to the stderr in red by default.
+  ///
+  /// The `stackTrace` argument is the stack trace that will be printed if
   /// supplied.
-  /// If the [emphasis] argument is true, it will cause the output message be
+  ///
+  /// If the `emphasis` argument is true, it will cause the output message be
   /// printed in bold text. Defaults to false.
-  /// The [color] argument will print the message in the supplied color instead
+  ///
+  /// The `color` argument will print the message in the supplied color instead
   /// of the default of red. Colors will not be printed if the output terminal
   /// doesn't support them.
-  /// If [newline] is true, then a newline will be added after printing the
+  ///
+  /// If `newline` is true, then a newline will be added after printing the
   /// status. Defaults to true.
-  /// The [indent] argument specifies the number of spaces to indent the overall
+  ///
+  /// The `indent` argument specifies the number of spaces to indent the overall
   /// message. If wrapping is enabled in [outputPreferences], then the wrapped
   /// lines will be indented as well.
-  /// If [hangingIndent] is specified, then any wrapped lines will be indented
+  ///
+  /// If `hangingIndent` is specified, then any wrapped lines will be indented
   /// by this much more than the first line, if wrapping is enabled in
   /// [outputPreferences].
-  /// If [wrap] is specified, then it overrides the
-  /// [outputPreferences.wrapText] setting.
+  ///
+  /// If `wrap` is specified, then it overrides the
+  /// `outputPreferences.wrapText` setting.
   void printStatus(
     String message, {
     bool emphasis,
@@ -89,17 +104,25 @@ abstract class Logger {
 
   /// Start an indeterminate progress display.
   ///
-  /// [message] is the message to display to the user; [progressId] provides an ID which can be
-  /// used to identify this type of progress (`hot.reload`, `hot.restart`, ...).
+  /// The `message` argument is the message to display to the user.
+  ///
+  /// The `timeout` argument sets a duration after which an additional message
+  /// may be shown saying that the operation is taking a long time. (Not all
+  /// [Status] subclasses show such a message.) Set this to null if the
+  /// operation can legitimately take an abritrary amount of time (e.g. waiting
+  /// for the user).
   ///
-  /// [progressIndicatorPadding] can optionally be used to specify spacing
-  /// between the [message] and the progress indicator.
+  /// The `progressId` argument provides an ID that can be used to identify
+  /// this type of progress (e.g. `hot.reload`, `hot.restart`).
+  ///
+  /// The `progressIndicatorPadding` can optionally be used to specify spacing
+  /// between the `message` and the progress indicator, if any.
   Status startProgress(
     String message, {
+    @required Duration timeout,
     String progressId,
-    bool expectSlowOperation,
-    bool multilineOutput,
-    int progressIndicatorPadding,
+    bool multilineOutput = false,
+    int progressIndicatorPadding = kDefaultStatusPadding,
   });
 }
 
@@ -119,17 +142,16 @@ class StdoutLogger extends Logger {
     int hangingIndent,
     bool wrap,
   }) {
+    _status?.pause();
     message ??= '';
     message = wrapText(message, indent: indent, hangingIndent: hangingIndent, shouldWrap: wrap);
-    _status?.cancel();
-    _status = null;
     if (emphasis == true)
       message = terminal.bolden(message);
     message = terminal.color(message, color ?? TerminalColor.red);
     stderr.writeln(message);
-    if (stackTrace != null) {
+    if (stackTrace != null)
       stderr.writeln(stackTrace.toString());
-    }
+    _status?.resume();
   }
 
   @override
@@ -142,10 +164,9 @@ class StdoutLogger extends Logger {
     int hangingIndent,
     bool wrap,
   }) {
+    _status?.pause();
     message ??= '';
     message = wrapText(message, indent: indent, hangingIndent: hangingIndent, shouldWrap: wrap);
-    _status?.cancel();
-    _status = null;
     if (emphasis == true)
       message = terminal.bolden(message);
     if (color != null)
@@ -153,6 +174,7 @@ class StdoutLogger extends Logger {
     if (newline != false)
       message = '$message\n';
     writeToStdOut(message);
+    _status?.resume();
   }
 
   @protected
@@ -166,21 +188,23 @@ class StdoutLogger extends Logger {
   @override
   Status startProgress(
     String message, {
+    @required Duration timeout,
     String progressId,
-    bool expectSlowOperation,
-    bool multilineOutput,
-    int progressIndicatorPadding,
+    bool multilineOutput = false,
+    int progressIndicatorPadding = kDefaultStatusPadding,
   }) {
-    expectSlowOperation ??= false;
-    progressIndicatorPadding ??= kDefaultStatusPadding;
+    assert(progressIndicatorPadding != null);
     if (_status != null) {
       // Ignore nested progresses; return a no-op status object.
-      return Status(onFinish: _clearStatus)..start();
+      return SilentStatus(
+        timeout: timeout,
+        onFinish: _clearStatus,
+      )..start();
     }
     if (terminal.supportsColor) {
       _status = AnsiStatus(
         message: message,
-        expectSlowOperation: expectSlowOperation,
+        timeout: timeout,
         multilineOutput: multilineOutput,
         padding: progressIndicatorPadding,
         onFinish: _clearStatus,
@@ -188,7 +212,7 @@ class StdoutLogger extends Logger {
     } else {
       _status = SummaryStatus(
         message: message,
-        expectSlowOperation: expectSlowOperation,
+        timeout: timeout,
         padding: progressIndicatorPadding,
         onFinish: _clearStatus,
       )..start();
@@ -270,13 +294,14 @@ class BufferLogger extends Logger {
   @override
   Status startProgress(
     String message, {
+    @required Duration timeout,
     String progressId,
-    bool expectSlowOperation,
-    bool multilineOutput,
-    int progressIndicatorPadding,
+    bool multilineOutput = false,
+    int progressIndicatorPadding = kDefaultStatusPadding,
   }) {
+    assert(progressIndicatorPadding != null);
     printStatus(message);
-    return Status()..start();
+    return SilentStatus(timeout: timeout)..start();
   }
 
   /// Clears all buffers.
@@ -337,15 +362,30 @@ class VerboseLogger extends Logger {
   @override
   Status startProgress(
     String message, {
+    @required Duration timeout,
     String progressId,
-    bool expectSlowOperation,
-    bool multilineOutput,
-    int progressIndicatorPadding,
+    bool multilineOutput = false,
+    int progressIndicatorPadding = kDefaultStatusPadding,
   }) {
+    assert(progressIndicatorPadding != null);
     printStatus(message);
-    return Status(onFinish: () {
-      printTrace('$message (completed)');
-    })..start();
+    final Stopwatch timer = Stopwatch()..start();
+    return SilentStatus(
+      timeout: timeout,
+      onFinish: () {
+        String time;
+        if (timeout == null || timeout > kFastOperation) {
+          time = getElapsedAsSeconds(timer.elapsed);
+        } else {
+          time = getElapsedAsMilliseconds(timer.elapsed);
+        }
+        if (timeout != null && timer.elapsed > timeout) {
+          printTrace('$message (completed in $time, longer than expected)');
+        } else {
+          printTrace('$message (completed in $time)');
+        }
+      },
+    )..start();
   }
 
   void _emit(_LogType type, String message, [StackTrace stackTrace]) {
@@ -383,10 +423,15 @@ class VerboseLogger extends Logger {
 
 enum _LogType { error, status, trace }
 
+typedef SlowWarningCallback = String Function();
+
 /// A [Status] class begins when start is called, and may produce progress
 /// information asynchronously.
 ///
-/// The [Status] class itself never has any output.
+/// Some subclasses change output once [timeout] has expired, to indicate that
+/// something is taking longer than expected.
+///
+/// The [SilentStatus] class never has any output.
 ///
 /// The [AnsiSpinner] subclass shows a spinner, and replaces it with a single
 /// space character when stopped or canceled.
@@ -395,51 +440,159 @@ enum _LogType { error, status, trace }
 /// information when stopped. When canceled, the information isn't shown. In
 /// either case, a newline is printed.
 ///
+/// The [SummaryStatus] subclass shows only a static message (without an
+/// indicator), then updates it when the operation ends.
+///
 /// Generally, consider `logger.startProgress` instead of directly creating
 /// a [Status] or one of its subclasses.
-class Status {
-  Status({this.onFinish});
+abstract class Status {
+  Status({ @required this.timeout, this.onFinish });
 
-  /// A straight [Status] or an [AnsiSpinner] (depending on whether the
+  /// A [SilentStatus] or an [AnsiSpinner] (depending on whether the
   /// terminal is fancy enough), already started.
-  factory Status.withSpinner({ VoidCallback onFinish }) {
+  factory Status.withSpinner({
+    @required Duration timeout,
+    VoidCallback onFinish,
+    SlowWarningCallback slowWarningCallback,
+  }) {
     if (terminal.supportsColor)
-      return AnsiSpinner(onFinish: onFinish)..start();
-    return Status(onFinish: onFinish)..start();
+      return AnsiSpinner(timeout: timeout, onFinish: onFinish, slowWarningCallback: slowWarningCallback)..start();
+    return SilentStatus(timeout: timeout, onFinish: onFinish)..start();
   }
 
+  final Duration timeout;
   final VoidCallback onFinish;
 
-  bool _isStarted = false;
+  @protected
+  final Stopwatch _stopwatch = Stopwatch();
+
+  @protected
+  bool get seemsSlow => timeout != null && _stopwatch.elapsed > timeout;
+
+  @protected
+  String get elapsedTime {
+    if (timeout == null || timeout > kFastOperation)
+      return getElapsedAsSeconds(_stopwatch.elapsed);
+    return getElapsedAsMilliseconds(_stopwatch.elapsed);
+  }
 
   /// Call to start spinning.
   void start() {
-    assert(!_isStarted);
-    _isStarted = true;
+    assert(!_stopwatch.isRunning);
+    _stopwatch.start();
   }
 
   /// Call to stop spinning after success.
   void stop() {
-    assert(_isStarted);
-    _isStarted = false;
-    if (onFinish != null)
-      onFinish();
+    finish();
   }
 
   /// Call to cancel the spinner after failure or cancellation.
   void cancel() {
-    assert(_isStarted);
-    _isStarted = false;
+    finish();
+  }
+
+  /// Call to clear the current line but not end the progress.
+  void pause() { }
+
+  /// Call to resume after a pause.
+  void resume() { }
+
+  @protected
+  void finish() {
+    assert(_stopwatch.isRunning);
+    _stopwatch.stop();
     if (onFinish != null)
       onFinish();
   }
 }
 
+/// A [SilentStatus] shows nothing.
+class SilentStatus extends Status {
+  SilentStatus({
+    @required Duration timeout,
+    VoidCallback onFinish,
+  }) : super(timeout: timeout, onFinish: onFinish);
+}
+
+/// Constructor writes [message] to [stdout].  On [cancel] or [stop], will call
+/// [onFinish]. On [stop], will additionally print out summary information.
+class SummaryStatus extends Status {
+  SummaryStatus({
+    this.message = '',
+    @required Duration timeout,
+    this.padding = kDefaultStatusPadding,
+    VoidCallback onFinish,
+  }) : assert(message != null),
+       assert(padding != null),
+       super(timeout: timeout, onFinish: onFinish);
+
+  final String message;
+  final int padding;
+
+  bool _messageShowingOnCurrentLine = false;
+
+  @override
+  void start() {
+    _printMessage();
+    super.start();
+  }
+
+  void _printMessage() {
+    assert(!_messageShowingOnCurrentLine);
+    stdout.write('${message.padRight(padding)}     ');
+    _messageShowingOnCurrentLine = true;
+  }
+
+  @override
+  void stop() {
+    if (!_messageShowingOnCurrentLine)
+      _printMessage();
+    super.stop();
+    writeSummaryInformation();
+    stdout.write('\n');
+  }
+
+  @override
+  void cancel() {
+    super.cancel();
+    if (_messageShowingOnCurrentLine)
+      stdout.write('\n');
+  }
+
+  /// Prints a (minimum) 8 character padded time.
+  ///
+  /// If [timeout] is less than or equal to [kFastOperation], the time is in
+  /// seconds; otherwise, milliseconds. If the time is longer than [timeout],
+  /// appends "(!)" to the time.
+  ///
+  /// Examples: `    0.5s`, `   150ms`, ` 1,600ms`, `    3.1s (!)`
+  void writeSummaryInformation() {
+    assert(_messageShowingOnCurrentLine);
+    stdout.write(elapsedTime.padLeft(_kTimePadding));
+    if (seemsSlow)
+      stdout.write(' (!)');
+  }
+
+  @override
+  void pause() {
+    super.pause();
+    stdout.write('\n');
+    _messageShowingOnCurrentLine = false;
+  }
+}
+
 /// An [AnsiSpinner] is a simple animation that does nothing but implement a
-/// ASCII/Unicode spinner. When stopped or canceled, the animation erases
-/// itself.
+/// terminal spinner. When stopped or canceled, the animation erases itself.
+///
+/// If the timeout expires, a customizable warning is shown (but the spinner
+/// continues otherwise unabated).
 class AnsiSpinner extends Status {
-  AnsiSpinner({VoidCallback onFinish}) : super(onFinish: onFinish);
+  AnsiSpinner({
+    @required Duration timeout,
+    VoidCallback onFinish,
+    this.slowWarningCallback,
+  }) : super(timeout: timeout, onFinish: onFinish);
 
   int ticks = 0;
   Timer timer;
@@ -449,73 +602,123 @@ class AnsiSpinner extends Status {
       ? <String>[r'-', r'\', r'|', r'/']
       : <String>['⣾', '⣽', '⣻', '⢿', '⡿', '⣟', '⣯', '⣷'];
 
-  String get _backspace => '\b' * _animation[0].length;
-  String get _clear => ' ' *  _animation[0].length;
+  static const String _defaultSlowWarning = '(This is taking an unexpectedly long time.)';
+  final SlowWarningCallback slowWarningCallback;
 
-  void _callback(Timer timer) {
-    stdout.write('$_backspace${_animation[ticks++ % _animation.length]}');
-  }
+  String _slowWarning = '';
+
+  String get _currentAnimationFrame => _animation[ticks % _animation.length];
+  int get _currentLength => _currentAnimationFrame.length + _slowWarning.length;
+  String get _backspace => '\b' * _currentLength;
+  String get _clear => ' ' *  _currentLength;
+
+  @protected
+  int get spinnerIndent => 0;
 
   @override
   void start() {
     super.start();
     assert(timer == null);
-    stdout.write(' ');
+    _startSpinner();
+  }
+
+  void _startSpinner() {
+    stdout.write(_clear * (spinnerIndent + 1)); // for _callback to backspace over
     timer = Timer.periodic(const Duration(milliseconds: 100), _callback);
     _callback(timer);
   }
 
+  void _callback(Timer timer) {
+    assert(this.timer == timer);
+    assert(timer != null);
+    assert(timer.isActive);
+    stdout.write('${_backspace * (spinnerIndent + 1)}');
+    ticks += 1;
+    stdout.write('${_clear * spinnerIndent}$_currentAnimationFrame');
+    if (seemsSlow) {
+      if (slowWarningCallback != null) {
+        _slowWarning = ' ' + slowWarningCallback();
+      } else {
+        _slowWarning = ' ' + _defaultSlowWarning;
+      }
+      stdout.write(_slowWarning);
+    }
+  }
+
   @override
-  void stop() {
+  void finish() {
+    assert(timer != null);
     assert(timer.isActive);
     timer.cancel();
-    stdout.write('$_backspace$_clear$_backspace');
-    super.stop();
+    timer = null;
+    _clearSpinner();
+    super.finish();
+  }
+
+  void _clearSpinner() {
+    final int width = spinnerIndent + 1;
+    stdout.write('${_backspace * width}${_clear * width}${_backspace * width}');
   }
 
   @override
-  void cancel() {
+  void pause() {
+    assert(timer != null);
     assert(timer.isActive);
+    _clearSpinner();
     timer.cancel();
-    stdout.write('$_backspace$_clear$_backspace');
-    super.cancel();
+  }
+
+  @override
+  void resume() {
+    assert(timer != null);
+    assert(!timer.isActive);
+    _startSpinner();
   }
 }
 
-/// Constructor writes [message] to [stdout] with padding, then starts as an
-/// [AnsiSpinner].  On [cancel] or [stop], will call [onFinish].
-/// On [stop], will additionally print out summary information in
-/// milliseconds if [expectSlowOperation] is false, as seconds otherwise.
+const int _kTimePadding = 8; // should fit "99,999ms"
+
+/// Constructor writes [message] to [stdout] with padding, then starts an
+/// indeterminate progress indicator animation (it's a subclass of
+/// [AnsiSpinner]).
+///
+/// On [cancel] or [stop], will call [onFinish]. On [stop], will
+/// additionally print out summary information.
 class AnsiStatus extends AnsiSpinner {
   AnsiStatus({
-    String message,
-    bool expectSlowOperation,
-    bool multilineOutput,
-    int padding,
+    this.message = '',
+    @required Duration timeout,
+    this.multilineOutput = false,
+    this.padding = kDefaultStatusPadding,
     VoidCallback onFinish,
-  })  : message = message ?? '',
-        padding = padding ?? 0,
-        expectSlowOperation = expectSlowOperation ?? false,
-        multilineOutput = multilineOutput ?? false,
-        super(onFinish: onFinish);
+  }) : assert(message != null),
+       assert(multilineOutput != null),
+       assert(padding != null),
+       super(timeout: timeout, onFinish: onFinish);
 
   final String message;
-  final bool expectSlowOperation;
   final bool multilineOutput;
   final int padding;
 
-  Stopwatch stopwatch;
-
   static const String _margin = '     ';
 
+  @override
+  int get spinnerIndent => _kTimePadding - 1;
+
+  int _totalMessageLength;
+
   @override
   void start() {
-    assert(stopwatch == null || !stopwatch.isRunning);
-    stopwatch = Stopwatch()..start();
-    stdout.write('${message.padRight(padding)}$_margin');
+    _startStatus();
     super.start();
   }
 
+  void _startStatus() {
+    final String line = '${message.padRight(padding)}$_margin';
+    _totalMessageLength = line.length;
+    stdout.write(line);
+  }
+
   @override
   void stop() {
     super.stop();
@@ -531,74 +734,31 @@ class AnsiStatus extends AnsiSpinner {
 
   /// Print summary information when a task is done.
   ///
-  /// If [multilineOutput] is false, backs up 4 characters and prints a
-  /// (minimum) 5 character padded time. If [expectSlowOperation] is true, the
-  /// time is in seconds; otherwise, milliseconds. Only backs up 4 characters
-  /// because [super.cancel] backs up one.
+  /// If [multilineOutput] is false, replaces the spinner with the summary message.
   ///
   /// If [multilineOutput] is true, then it prints the message again on a new
-  /// line before writing the elapsed time, and doesn't back up at all.
+  /// line before writing the elapsed time.
   void writeSummaryInformation() {
-    final String prefix = multilineOutput
-        ? '\n${'$message Done'.padRight(padding - 4)}$_margin'
-        : '\b\b\b\b';
-    if (expectSlowOperation) {
-      stdout.write('$prefix${getElapsedAsSeconds(stopwatch.elapsed).padLeft(5)}');
-    } else {
-      stdout.write('$prefix${getElapsedAsMilliseconds(stopwatch.elapsed).padLeft(5)}');
-    }
+    if (multilineOutput)
+      stdout.write('\n${'$message Done'.padRight(padding)}$_margin');
+    stdout.write(elapsedTime.padLeft(_kTimePadding));
+    if (seemsSlow)
+      stdout.write(' (!)');
   }
-}
-
-/// Constructor writes [message] to [stdout].  On [cancel] or [stop], will call
-/// [onFinish]. On [stop], will additionally print out summary information in
-/// milliseconds if [expectSlowOperation] is false, as seconds otherwise.
-class SummaryStatus extends Status {
-  SummaryStatus({
-    String message,
-    bool expectSlowOperation,
-    int padding,
-    VoidCallback onFinish,
-  })  : message = message ?? '',
-        padding = padding ?? 0,
-        expectSlowOperation = expectSlowOperation ?? false,
-        super(onFinish: onFinish);
 
-  final String message;
-  final bool expectSlowOperation;
-  final int padding;
-
-  Stopwatch stopwatch;
-
-  @override
-  void start() {
-    stopwatch = Stopwatch()..start();
-    stdout.write('${message.padRight(padding)}     ');
-    super.start();
+  void _clearStatus() {
+    stdout.write('${_backspace * _totalMessageLength}${_clear * _totalMessageLength}${_backspace * _totalMessageLength}');
   }
 
   @override
-  void stop() {
-    super.stop();
-    writeSummaryInformation();
-    stdout.write('\n');
+  void pause() {
+    super.pause();
+    _clearStatus();
   }
 
   @override
-  void cancel() {
-    super.cancel();
-    stdout.write('\n');
-  }
-
-  /// Prints a (minimum) 5 character padded time.  If [expectSlowOperation] is
-  /// true, the time is in seconds; otherwise, milliseconds.
-  ///
-  /// Example: ' 0.5s', '150ms', '1600ms'
-  void writeSummaryInformation() {
-    if (expectSlowOperation) {
-      stdout.write(getElapsedAsSeconds(stopwatch.elapsed).padLeft(5));
-    } else {
-      stdout.write(getElapsedAsMilliseconds(stopwatch.elapsed).padLeft(5));
-    }
+  void resume() {
+    _startStatus();
+    super.resume();
   }
 }

packages/flutter_tools/lib/src/base/net.dart

@@ -37,7 +37,7 @@ Future<List<int>> _attempt(Uri url, {bool onlyHeaders = false}) async {
   printTrace('Downloading: $url');
   HttpClient httpClient;
   if (context[HttpClientFactory] != null) {
-    httpClient = context[HttpClientFactory]();
+    httpClient = (context[HttpClientFactory] as HttpClientFactory)(); // ignore: avoid_as
   } else {
     httpClient = HttpClient();
   }

packages/flutter_tools/lib/src/base/process.dart

@@ -203,14 +203,6 @@ Future<int> runInteractively(List<String> command, {
   return await process.exitCode;
 }
 
-Future<void> runAndKill(List<String> cmd, Duration timeout) {
-  final Future<Process> proc = runDetached(cmd);
-  return Future<void>.delayed(timeout, () async {
-    printTrace('Intentionally killing ${cmd[0]}');
-    processManager.killPid((await proc).pid);
-  });
-}
-
 Future<Process> runDetached(List<String> cmd) {
   _traceCommand(cmd);
   final Future<Process> proc = processManager.start(

packages/flutter_tools/lib/src/base/terminal.dart

@@ -5,8 +5,6 @@
 import 'dart:async';
 import 'dart:convert' show AsciiDecoder;
 
-import 'package:quiver/strings.dart';
-
 import '../globals.dart';
 import 'context.dart';
 import 'io.dart' as io;
@@ -172,31 +170,32 @@ class AnsiTerminal {
   /// Return keystrokes from the console.
   ///
   /// Useful when the console is in [singleCharMode].
-  Stream<String> get onCharInput {
+  Stream<String> get keystrokes {
     _broadcastStdInString ??= io.stdin.transform<String>(const AsciiDecoder(allowInvalid: true)).asBroadcastStream();
     return _broadcastStdInString;
   }
 
-  /// Prompts the user to input a character within the accepted list. Re-prompts
-  /// if entered character is not in the list.
+  /// Prompts the user to input a character within a given list. Re-prompts if
+  /// entered character is not in the list.
   ///
-  /// The [prompt] is the text displayed prior to waiting for user input. The
-  /// [defaultChoiceIndex], if given, will be the character appearing in
-  /// [acceptedCharacters] in the index given if the user presses enter without
-  /// any key input. Setting [displayAcceptedCharacters] also prints the
-  /// accepted keys next to the [prompt].
+  /// The `prompt`, if non-null, is the text displayed prior to waiting for user
+  /// input each time. If `prompt` is non-null and `displayAcceptedCharacters`
+  /// is true, the accepted keys are printed next to the `prompt`.
   ///
-  /// Throws a [TimeoutException] if a `timeout` is provided and its duration
-  /// expired without user input. Duration resets per key press.
+  /// The returned value is the user's input; if `defaultChoiceIndex` is not
+  /// null, and the user presses enter without any other input, the return value
+  /// will be the character in `acceptedCharacters` at the index given by
+  /// `defaultChoiceIndex`.
   Future<String> promptForCharInput(
     List<String> acceptedCharacters, {
     String prompt,
     int defaultChoiceIndex,
     bool displayAcceptedCharacters = true,
-    Duration timeout,
   }) async {
     assert(acceptedCharacters != null);
     assert(acceptedCharacters.isNotEmpty);
+    assert(prompt == null || prompt.isNotEmpty);
+    assert(displayAcceptedCharacters != null);
     List<String> charactersToDisplay = acceptedCharacters;
     if (defaultChoiceIndex != null) {
       assert(defaultChoiceIndex >= 0 && defaultChoiceIndex < acceptedCharacters.length);
@@ -206,17 +205,14 @@ class AnsiTerminal {
     }
     String choice;
     singleCharMode = true;
-    while (isEmpty(choice) || choice.length != 1 || !acceptedCharacters.contains(choice)) {
-      if (isNotEmpty(prompt)) {
+    while (choice == null || choice.length > 1 || !acceptedCharacters.contains(choice)) {
+      if (prompt != null) {
         printStatus(prompt, emphasis: true, newline: false);
         if (displayAcceptedCharacters)
           printStatus(' [${charactersToDisplay.join("|")}]', newline: false);
         printStatus(': ', emphasis: true, newline: false);
       }
-      Future<String> inputFuture = onCharInput.first;
-      if (timeout != null)
-        inputFuture = inputFuture.timeout(timeout);
-      choice = await inputFuture;
+      choice = await keystrokes.first;
       printStatus(choice);
     }
     singleCharMode = false;

packages/flutter_tools/lib/src/cache.dart

@@ -299,7 +299,7 @@ abstract class CachedArtifact {
   Future<void> _downloadArchive(String message, Uri url, Directory location, bool verifier(File f), void extractor(File f, Directory d)) {
     return _withDownloadFile('${flattenNameSubdirs(url)}', (File tempFile) async {
       if (!verifier(tempFile)) {
-        final Status status = logger.startProgress(message, expectSlowOperation: true);
+        final Status status = logger.startProgress(message, timeout: kSlowOperation);
         try {
           await _downloadFile(url, tempFile);
           status.stop();
@@ -648,7 +648,7 @@ Future<void> _downloadFile(Uri url, File location) async {
 }
 
 Future<bool> _doesRemoteExist(String message, Uri url) async {
-  final Status status = logger.startProgress(message, expectSlowOperation: true);
+  final Status status = logger.startProgress(message, timeout: kSlowOperation);
   final bool exists = await doesRemoteFileExist(url);
   status.stop();
   return exists;

packages/flutter_tools/lib/src/commands/analyze_continuously.dart

@@ -74,11 +74,12 @@ class AnalyzeContinuously extends AnalyzeBase {
       analysisStatus?.cancel();
       if (!firstAnalysis)
         printStatus('\n');
-      analysisStatus = logger.startProgress('Analyzing $analysisTarget...');
+      analysisStatus = logger.startProgress('Analyzing $analysisTarget...', timeout: kSlowOperation);
       analyzedPaths.clear();
       analysisTimer = Stopwatch()..start();
     } else {
       analysisStatus?.stop();
+      analysisStatus = null;
       analysisTimer.stop();
 
       logger.printStatus(terminal.clearScreen(), newline: false);

packages/flutter_tools/lib/src/commands/analyze_once.dart

@@ -107,7 +107,7 @@ class AnalyzeOnce extends AnalyzeBase {
         ? '${directories.length} ${directories.length == 1 ? 'directory' : 'directories'}'
         : fs.path.basename(directories.first);
     final Status progress = argResults['preamble']
-        ? logger.startProgress('Analyzing $message...')
+        ? logger.startProgress('Analyzing $message...', timeout: kSlowOperation)
         : null;
 
     await analysisCompleter.future;

packages/flutter_tools/lib/src/commands/attach.dart

@@ -135,15 +135,14 @@ class AttachCommand extends FlutterCommand {
       if (device is FuchsiaDevice) {
         attachLogger = true;
         final String module = argResults['module'];
-        if (module == null) {
-          throwToolExit('\'--module\' is requried for attaching to a Fuchsia device');
-        }
+        if (module == null)
+          throwToolExit('\'--module\' is required for attaching to a Fuchsia device');
         usesIpv6 = device.ipv6;
         FuchsiaIsolateDiscoveryProtocol isolateDiscoveryProtocol;
         try {
           isolateDiscoveryProtocol = device.getIsolateDiscoveryProtocol(module);
           observatoryUri = await isolateDiscoveryProtocol.uri;
-          printStatus('Done.');
+          printStatus('Done.'); // FYI, this message is used as a sentinel in tests.
         } catch (_) {
           isolateDiscoveryProtocol?.dispose();
           final List<ForwardedPort> ports = device.portForwarder.forwardedPorts.toList();
@@ -163,7 +162,7 @@ class AttachCommand extends FlutterCommand {
           observatoryUri = await observatoryDiscovery.uri;
           // Determine ipv6 status from the scanned logs.
           usesIpv6 = observatoryDiscovery.ipv6;
-          printStatus('Done.');
+          printStatus('Done.'); // FYI, this message is used as a sentinel in tests.
         } finally {
           await observatoryDiscovery?.cancel();
         }
@@ -210,20 +209,30 @@ class AttachCommand extends FlutterCommand {
       if (attachLogger) {
         flutterDevice.startEchoingDeviceLog();
       }
+
+      int result;
       if (daemon != null) {
         AppInstance app;
         try {
-          app = await daemon.appDomain.launch(runner, runner.attach,
-              device, null, true, fs.currentDirectory);
+          app = await daemon.appDomain.launch(
+            runner,
+            runner.attach,
+            device,
+            null,
+            true,
+            fs.currentDirectory,
+          );
         } catch (error) {
           throwToolExit(error.toString());
         }
-        final int result = await app.runner.waitForAppToFinish();
-        if (result != 0)
-          throwToolExit(null, exitCode: result);
+        result = await app.runner.waitForAppToFinish();
+        assert(result != null);
       } else {
-        await runner.attach();
+        result = await runner.attach();
+        assert(result != null);
       }
+      if (result != 0)
+        throwToolExit(null, exitCode: result);
     } finally {
       final List<ForwardedPort> ports = device.portForwarder.forwardedPorts.toList();
       for (ForwardedPort port in ports) {

packages/flutter_tools/lib/src/commands/build.dart

@@ -4,11 +4,6 @@
 
 import 'dart:async';
 
-import 'package:meta/meta.dart';
-
-import '../base/file_system.dart';
-import '../base/utils.dart';
-import '../globals.dart';
 import '../runner/flutter_command.dart';
 import 'build_aot.dart';
 import 'build_apk.dart';
@@ -41,25 +36,4 @@ abstract class BuildSubCommand extends FlutterCommand {
   BuildSubCommand() {
     requiresPubspecYaml();
   }
-
-  @override
-  @mustCallSuper
-  Future<FlutterCommandResult> runCommand() async {
-    if (isRunningOnBot) {
-      final File dotPackages = fs.file('.packages');
-      printStatus('Contents of .packages:');
-      if (dotPackages.existsSync())
-        printStatus(dotPackages.readAsStringSync());
-      else
-        printError('File not found: ${dotPackages.absolute.path}');
-
-      final File pubspecLock = fs.file('pubspec.lock');
-      printStatus('Contents of pubspec.lock:');
-      if (pubspecLock.existsSync())
-        printStatus(pubspecLock.readAsStringSync());
-      else
-        printError('File not found: ${pubspecLock.absolute.path}');
-    }
-    return null;
-  }
 }

packages/flutter_tools/lib/src/commands/build_aot.dart

@@ -57,8 +57,6 @@ class BuildAotCommand extends BuildSubCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    await super.runCommand();
-
     final String targetPlatform = argResults['target-platform'];
     final TargetPlatform platform = getTargetPlatformForName(targetPlatform);
     if (platform == null)
@@ -71,7 +69,7 @@ class BuildAotCommand extends BuildSubCommand {
       final String typeName = artifacts.getEngineType(platform, buildMode);
       status = logger.startProgress(
         'Building AOT snapshot in ${getFriendlyModeName(getBuildMode())} mode ($typeName)...',
-        expectSlowOperation: true,
+        timeout: kSlowOperation,
       );
     }
     final String outputPath = argResults['output-dir'] ?? getAotBuildDirectory();

packages/flutter_tools/lib/src/commands/build_apk.dart

@@ -42,7 +42,6 @@ class BuildApkCommand extends BuildSubCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    await super.runCommand();
     await buildApk(
       project: await FlutterProject.current(),
       target: targetFile,

packages/flutter_tools/lib/src/commands/build_appbundle.dart

@@ -40,7 +40,6 @@ class BuildAppBundleCommand extends BuildSubCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    await super.runCommand();
     await buildAppBundle(
       project: await FlutterProject.current(),
       target: targetFile,

packages/flutter_tools/lib/src/commands/build_bundle.dart

@@ -65,8 +65,6 @@ class BuildBundleCommand extends BuildSubCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    await super.runCommand();
-
     final String targetPlatform = argResults['target-platform'];
     final TargetPlatform platform = getTargetPlatformForName(targetPlatform);
     if (platform == null)

packages/flutter_tools/lib/src/commands/build_flx.dart

@@ -20,12 +20,9 @@ class BuildFlxCommand extends BuildSubCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    await super.runCommand();
-
     printError("'build flx' is no longer supported. Instead, use 'build "
                "bundle' to build and assemble the application code and resources "
                'for your app.');
-
     return null;
   }
 }

packages/flutter_tools/lib/src/commands/build_ios.dart

@@ -53,7 +53,6 @@ class BuildIOSCommand extends BuildSubCommand {
     final bool forSimulator = argResults['simulator'];
     defaultBuildMode = forSimulator ? BuildMode.debug : BuildMode.release;
 
-    await super.runCommand();
     if (getCurrentHostPlatform() != HostPlatform.darwin_x64)
       throwToolExit('Building for iOS is only supported on the Mac.');
 

packages/flutter_tools/lib/src/commands/daemon.dart

@@ -383,16 +383,22 @@ class AppDomain extends Domain {
     }
 
     return launch(
-        runner,
-        ({ Completer<DebugConnectionInfo> connectionInfoCompleter,
-            Completer<void> appStartedCompleter }) => runner.run(
-                connectionInfoCompleter: connectionInfoCompleter,
-                appStartedCompleter: appStartedCompleter,
-                route: route),
-        device,
-        projectDirectory,
-        enableHotReload,
-        cwd);
+      runner,
+      ({
+        Completer<DebugConnectionInfo> connectionInfoCompleter,
+        Completer<void> appStartedCompleter,
+      }) {
+        return runner.run(
+          connectionInfoCompleter: connectionInfoCompleter,
+          appStartedCompleter: appStartedCompleter,
+          route: route,
+        );
+      },
+      device,
+      projectDirectory,
+      enableHotReload,
+      cwd,
+    );
   }
 
   Future<AppInstance> launch(
@@ -428,17 +434,19 @@ class AppDomain extends Domain {
       });
     }
     final Completer<void> appStartedCompleter = Completer<void>();
-    // We don't want to wait for this future to complete and callbacks won't fail.
-    // As it just writes to stdout.
-    appStartedCompleter.future.then<void>((_) { // ignore: unawaited_futures
-      _sendAppEvent(app, 'started');
-    });
+    // We don't want to wait for this future to complete, and callbacks won't fail,
+    // as it just writes to stdout.
+    appStartedCompleter.future // ignore: unawaited_futures
+      .then<void>((void value) {
+        _sendAppEvent(app, 'started');
+      });
 
     await app._runInZone<void>(this, () async {
       try {
         await runOrAttach(
-            connectionInfoCompleter: connectionInfoCompleter,
-            appStartedCompleter: appStartedCompleter);
+          connectionInfoCompleter: connectionInfoCompleter,
+          appStartedCompleter: appStartedCompleter,
+        );
         _sendAppEvent(app, 'stop');
       } catch (error, trace) {
         _sendAppEvent(app, 'stop', <String, dynamic>{
@@ -515,14 +523,15 @@ class AppDomain extends Domain {
     if (app == null)
       throw "app '$appId' not found";
 
-    return app.stop().timeout(const Duration(seconds: 5)).then<bool>((_) {
-      return true;
-    }).catchError((dynamic error) {
-      _sendAppEvent(app, 'log', <String, dynamic>{ 'log': '$error', 'error': true });
-      app.closeLogger();
-      _apps.remove(app);
-      return false;
-    });
+    return app.stop().then<bool>(
+      (void value) => true,
+      onError: (dynamic error, StackTrace stack) {
+        _sendAppEvent(app, 'log', <String, dynamic>{ 'log': '$error', 'error': true });
+        app.closeLogger();
+        _apps.remove(app);
+        return false;
+      },
+    );
   }
 
   Future<bool> detach(Map<String, dynamic> args) async {
@@ -532,14 +541,15 @@ class AppDomain extends Domain {
     if (app == null)
       throw "app '$appId' not found";
 
-    return app.detach().timeout(const Duration(seconds: 5)).then<bool>((_) {
-      return true;
-    }).catchError((dynamic error) {
-      _sendAppEvent(app, 'log', <String, dynamic>{ 'log': '$error', 'error': true });
-      app.closeLogger();
-      _apps.remove(app);
-      return false;
-    });
+    return app.detach().then<bool>(
+      (void value) => true,
+      onError: (dynamic error, StackTrace stack) {
+        _sendAppEvent(app, 'log', <String, dynamic>{ 'log': '$error', 'error': true });
+        app.closeLogger();
+        _apps.remove(app);
+        return false;
+      },
+    );
   }
 
   AppInstance _getApp(String id) {
@@ -772,13 +782,14 @@ class NotifyingLogger extends Logger {
   @override
   Status startProgress(
     String message, {
+    @required Duration timeout,
     String progressId,
-    bool expectSlowOperation = false,
     bool multilineOutput,
     int progressIndicatorPadding = kDefaultStatusPadding,
   }) {
+    assert(timeout != null);
     printStatus(message);
-    return Status();
+    return SilentStatus(timeout: timeout);
   }
 
   void dispose() {
@@ -948,11 +959,12 @@ class _AppRunLogger extends Logger {
   @override
   Status startProgress(
     String message, {
+    @required Duration timeout,
     String progressId,
-    bool expectSlowOperation = false,
     bool multilineOutput,
     int progressIndicatorPadding = 52,
   }) {
+    assert(timeout != null);
     final int id = _nextProgressId++;
 
     _sendProgressEvent(<String, dynamic>{
@@ -961,13 +973,16 @@ class _AppRunLogger extends Logger {
       'message': message,
     });
 
-    _status = Status(onFinish: () {
-      _status = null;
-      _sendProgressEvent(<String, dynamic>{
-        'id': id.toString(),
-        'progressId': progressId,
-        'finished': true
-      });
+    _status = SilentStatus(
+      timeout: timeout,
+      onFinish: () {
+        _status = null;
+        _sendProgressEvent(<String, dynamic>{
+          'id': id.toString(),
+          'progressId': progressId,
+          'finished': true,
+        },
+      );
     })..start();
     return _status;
   }

packages/flutter_tools/lib/src/commands/logs.dart

@@ -29,11 +29,11 @@ class LogsCommand extends FlutterCommand {
   Device device;
 
   @override
-  Future<FlutterCommandResult> verifyThenRunCommand() async {
+  Future<FlutterCommandResult> verifyThenRunCommand(String commandPath) async {
     device = await findTargetDevice();
     if (device == null)
       throwToolExit(null);
-    return super.verifyThenRunCommand();
+    return super.verifyThenRunCommand(commandPath);
   }
 
   @override

packages/flutter_tools/lib/src/commands/run.dart

@@ -17,9 +17,9 @@ import '../resident_runner.dart';
 import '../run_cold.dart';
 import '../run_hot.dart';
 import '../runner/flutter_command.dart';
+import '../tracing.dart';
 import 'daemon.dart';
 
-// TODO(mklim): Test this, flutter/flutter#23031.
 abstract class RunCommandBase extends FlutterCommand {
   // Used by run and drive commands.
   RunCommandBase({ bool verboseHelp = false }) {
@@ -30,7 +30,7 @@ abstract class RunCommandBase extends FlutterCommand {
     argParser
       ..addFlag('trace-startup',
         negatable: false,
-        help: 'Start tracing during startup.',
+        help: 'Trace application startup, then exit, saving the trace to a file.',
       )
       ..addOption('route',
         help: 'Which route to load when running the app.',
@@ -90,6 +90,14 @@ class RunCommand extends RunCommandBase {
         help: 'Enable tracing of Skia code. This is useful when debugging '
               'the GPU thread. By default, Flutter will not log skia code.',
       )
+      ..addFlag('await-first-frame-when-tracing',
+        defaultsTo: true,
+        help: 'Whether to wait for the first frame when tracing startup ("--trace-startup"), '
+              'or just dump the trace as soon as the application is running. The first frame '
+              'is detected by looking for a Timeline event with the name '
+              '"${Tracing.firstUsefulFrameEventName}". '
+              'By default, the widgets library\'s binding takes care of sending this event. ',
+      )
       ..addFlag('use-test-fonts',
         negatable: true,
         help: 'Enable (and default to) the "Ahem" font. This is a special font '
@@ -108,7 +116,7 @@ class RunCommand extends RunCommandBase {
       )
       ..addFlag('track-widget-creation',
         hide: !verboseHelp,
-        help: 'Track widget creation locations. Requires Dart 2.0 functionality.',
+        help: 'Track widget creation locations.',
       )
       ..addOption('project-root',
         hide: !verboseHelp,
@@ -123,18 +131,18 @@ class RunCommand extends RunCommandBase {
       ..addFlag('hot',
         negatable: true,
         defaultsTo: kHotReloadDefault,
-        help: 'Run with support for hot reloading.',
-      )
-      ..addOption('pid-file',
-        help: 'Specify a file to write the process id to. '
-              'You can send SIGUSR1 to trigger a hot reload '
-              'and SIGUSR2 to trigger a hot restart.',
+        help: 'Run with support for hot reloading. Only available for debug mode. Not available with "--trace-startup".',
       )
       ..addFlag('resident',
         negatable: true,
         defaultsTo: true,
         hide: !verboseHelp,
-        help: 'Stay resident after launching the application.',
+        help: 'Stay resident after launching the application. Not available with "--trace-startup".',
+      )
+      ..addOption('pid-file',
+        help: 'Specify a file to write the process id to. '
+              'You can send SIGUSR1 to trigger a hot reload '
+              'and SIGUSR2 to trigger a hot restart.',
       )
       ..addFlag('benchmark',
         negatable: false,
@@ -206,7 +214,7 @@ class RunCommand extends RunCommandBase {
 
   bool shouldUseHotMode() {
     final bool hotArg = argResults['hot'] ?? false;
-    final bool shouldUseHotMode = hotArg;
+    final bool shouldUseHotMode = hotArg && !traceStartup;
     return getBuildInfo().isDebug && shouldUseHotMode;
   }
 
@@ -214,6 +222,7 @@ class RunCommand extends RunCommandBase {
       argResults['use-application-binary'] != null;
 
   bool get stayResident => argResults['resident'];
+  bool get awaitFirstFrameWhenTracing => argResults['await-first-frame-when-tracing'];
 
   @override
   Future<void> validateCommand() async {
@@ -359,6 +368,7 @@ class RunCommand extends RunCommandBase {
         target: targetFile,
         debuggingOptions: _createDebuggingOptions(),
         traceStartup: traceStartup,
+        awaitFirstFrameWhenTracing: awaitFirstFrameWhenTracing,
         applicationBinary: applicationBinaryPath == null
             ? null
             : fs.file(applicationBinaryPath),

packages/flutter_tools/lib/src/commands/screenshot.dart

@@ -64,7 +64,7 @@ class ScreenshotCommand extends FlutterCommand {
   Device device;
 
   @override
-  Future<FlutterCommandResult> verifyThenRunCommand() async {
+  Future<FlutterCommandResult> verifyThenRunCommand(String commandPath) async {
     device = await findTargetDevice();
     if (device == null)
       throwToolExit('Must have a connected device');
@@ -72,7 +72,7 @@ class ScreenshotCommand extends FlutterCommand {
       throwToolExit('Screenshot not supported for ${device.name}.');
     if (argResults[_kType] != _kDeviceType && argResults[_kObservatoryPort] == null)
       throwToolExit('Observatory port must be specified for screenshot type ${argResults[_kType]}');
-    return super.verifyThenRunCommand();
+    return super.verifyThenRunCommand(commandPath);
   }
 
   @override

packages/flutter_tools/lib/src/commands/update_packages.dart

@@ -87,7 +87,7 @@ class UpdatePackagesCommand extends FlutterCommand {
   Future<void> _downloadCoverageData() async {
     final Status status = logger.startProgress(
       'Downloading lcov data for package:flutter...',
-      expectSlowOperation: true,
+      timeout: kSlowOperation,
     );
     final String urlBase = platform.environment['FLUTTER_STORAGE_BASE_URL'] ?? 'https://storage.googleapis.com';
     final List<int> data = await fetchUrl(Uri.parse('$urlBase/flutter_infra/flutter/coverage/lcov.info'));

packages/flutter_tools/lib/src/dart/pub.dart

@@ -92,7 +92,7 @@ Future<void> pubGet({
     final String command = upgrade ? 'upgrade' : 'get';
     final Status status = logger.startProgress(
       'Running "flutter packages $command" in ${fs.path.basename(directory)}...',
-      expectSlowOperation: true,
+      timeout: kSlowOperation,
     );
     final List<String> args = <String>['--verbosity=warning'];
     if (FlutterCommand.current != null && FlutterCommand.current.globalResults['verbose'])

packages/flutter_tools/lib/src/device.dart

@@ -156,7 +156,7 @@ abstract class PollingDeviceDiscovery extends DeviceDiscovery {
           final List<Device> devices = await pollingGetDevices().timeout(_pollingTimeout);
           _items.updateWithNewList(devices);
         } on TimeoutException {
-          printTrace('Device poll timed out.');
+          printTrace('Device poll timed out. Will retry.');
         }
       }, _pollingInterval);
     }

packages/flutter_tools/lib/src/doctor.dart

@@ -188,7 +188,10 @@ class Doctor {
 
     for (ValidatorTask validatorTask in startValidatorTasks()) {
       final DoctorValidator validator = validatorTask.validator;
-      final Status status = Status.withSpinner();
+      final Status status = Status.withSpinner(
+        timeout: kFastOperation,
+        slowWarningCallback: () => validator.slowWarning,
+      );
       ValidationResult result;
       try {
         result = await validatorTask.result;
@@ -290,6 +293,8 @@ abstract class DoctorValidator {
 
   final String title;
 
+  String get slowWarning => 'This is taking an unexpectedly long time...';
+
   Future<ValidationResult> validate();
 }
 
@@ -302,6 +307,10 @@ class GroupedValidator extends DoctorValidator {
 
   final List<DoctorValidator> subValidators;
 
+  @override
+  String get slowWarning => _currentSlowWarning;
+  String _currentSlowWarning = 'Initializing...';
+
   @override
   Future<ValidationResult> validate() async  {
     final List<ValidatorTask> tasks = <ValidatorTask>[];
@@ -311,8 +320,10 @@ class GroupedValidator extends DoctorValidator {
 
     final List<ValidationResult> results = <ValidationResult>[];
     for (ValidatorTask subValidator in tasks) {
+      _currentSlowWarning = subValidator.validator.slowWarning;
       results.add(await subValidator.result);
     }
+    _currentSlowWarning = 'Merging results...';
     return _mergeValidationResults(results);
   }
 
@@ -675,6 +686,9 @@ class IntelliJValidatorOnMac extends IntelliJValidator {
 class DeviceValidator extends DoctorValidator {
   DeviceValidator() : super('Connected device');
 
+  @override
+  String get slowWarning => 'Scanning for devices is taking a long time...';
+
   @override
   Future<ValidationResult> validate() async {
     final List<Device> devices = await deviceManager.getAllConnectedDevices().toList();

packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart

@@ -325,7 +325,7 @@ class FuchsiaIsolateDiscoveryProtocol {
     }
     _status ??= logger.startProgress(
       'Waiting for a connection from $_isolateName on ${_device.name}...',
-      expectSlowOperation: true,
+      timeout: null, // could take an arbitrary amount of time
     );
     _pollingTimer ??= Timer(_pollDuration, _findIsolate);
     return _foundUri.future.then((Uri uri) {

packages/flutter_tools/lib/src/ios/cocoapods.dart

@@ -237,7 +237,7 @@ class CocoaPods {
   }
 
   Future<void> _runPodInstall(IosProject iosProject, String engineDirectory) async {
-    final Status status = logger.startProgress('Running pod install...', expectSlowOperation: true);
+    final Status status = logger.startProgress('Running pod install...', timeout: kSlowOperation);
     final ProcessResult result = await processManager.run(
       <String>['pod', 'install', '--verbose'],
       workingDirectory: iosProject.hostAppRoot.path,

packages/flutter_tools/lib/src/ios/devices.dart

@@ -26,8 +26,6 @@ const String _kIdeviceinstallerInstructions =
     'To work with iOS devices, please install ideviceinstaller. To install, run:\n'
     'brew install ideviceinstaller.';
 
-const Duration kPortForwardTimeout = Duration(seconds: 10);
-
 class IOSDeploy {
   const IOSDeploy();
 
@@ -297,7 +295,7 @@ class IOSDevice extends Device {
     int installationResult = -1;
     Uri localObservatoryUri;
 
-    final Status installStatus = logger.startProgress('Installing and launching...', expectSlowOperation: true);
+    final Status installStatus = logger.startProgress('Installing and launching...', timeout: kSlowOperation);
 
     if (!debuggingOptions.debuggingEnabled) {
       // If debugging is not enabled, just launch the application and continue.

packages/flutter_tools/lib/src/ios/mac.dart

@@ -470,7 +470,7 @@ Future<XcodeBuildResult> buildXcodeProject({
           initialBuildStatus.cancel();
           buildSubStatus = logger.startProgress(
             line,
-            expectSlowOperation: true,
+            timeout: kSlowOperation,
             progressIndicatorPadding: kDefaultStatusPadding - 7,
           );
         }
@@ -485,7 +485,7 @@ Future<XcodeBuildResult> buildXcodeProject({
   }
 
   final Stopwatch buildStopwatch = Stopwatch()..start();
-  initialBuildStatus = logger.startProgress('Starting Xcode build...');
+  initialBuildStatus = logger.startProgress('Starting Xcode build...', timeout: kFastOperation);
   final RunResult buildResult = await runAsync(
     buildCommands,
     workingDirectory: app.project.hostAppRoot.path,

packages/flutter_tools/lib/src/resident_runner.dart

@@ -9,7 +9,6 @@ import 'package:meta/meta.dart';
 import 'application_package.dart';
 import 'artifacts.dart';
 import 'asset.dart';
-import 'base/common.dart';
 import 'base/file_system.dart';
 import 'base/io.dart';
 import 'base/logger.dart';
@@ -76,12 +75,14 @@ class FlutterDevice {
     if (vmServices != null)
       return;
     final List<VMService> localVmServices = List<VMService>(observatoryUris.length);
-    for (int i = 0; i < observatoryUris.length; i++) {
+    for (int i = 0; i < observatoryUris.length; i += 1) {
       printTrace('Connecting to service protocol: ${observatoryUris[i]}');
-      localVmServices[i] = await VMService.connect(observatoryUris[i],
-          reloadSources: reloadSources,
-          restart: restart,
-          compileExpression: compileExpression);
+      localVmServices[i] = await VMService.connect(
+        observatoryUris[i],
+        reloadSources: reloadSources,
+        restart: restart,
+        compileExpression: compileExpression,
+      );
       printTrace('Successfully connected to service protocol: ${observatoryUris[i]}');
     }
     vmServices = localVmServices;
@@ -102,9 +103,13 @@ class FlutterDevice {
 
     return vmServices
       .where((VMService service) => !service.isClosed)
-      .expand<FlutterView>((VMService service) => viewFilter != null
-          ? service.vm.allViewsWithName(viewFilter)
-          : service.vm.views)
+      .expand<FlutterView>(
+        (VMService service) {
+          return viewFilter != null
+               ? service.vm.allViewsWithName(viewFilter)
+               : service.vm.views;
+        },
+      )
       .toList();
   }
 
@@ -120,13 +125,16 @@ class FlutterDevice {
     final List<FlutterView> flutterViews = views;
     if (flutterViews == null || flutterViews.isEmpty)
       return;
+    final List<Future<void>> futures = <Future<void>>[];
     for (FlutterView view in flutterViews) {
       if (view != null && view.uiIsolate != null) {
-        // Manage waits specifically below.
-        view.uiIsolate.flutterExit(); // ignore: unawaited_futures
+        futures.add(view.uiIsolate.flutterExit());
       }
     }
-    await Future<void>.delayed(const Duration(milliseconds: 100));
+    // The flutterExit message only returns if it fails, so just wait a few
+    // seconds then assume it worked.
+    // TODO(ianh): We should make this return once the VM service disconnects.
+    await Future.wait(futures).timeout(const Duration(seconds: 2), onTimeout: () { });
   }
 
   Future<Uri> setupDevFS(String fsName,
@@ -390,7 +398,7 @@ class FlutterDevice {
   }) async {
     final Status devFSStatus = logger.startProgress(
       'Syncing files to device ${device.name}...',
-      expectSlowOperation: true,
+      timeout: kFastOperation,
     );
     UpdateFSReport report;
     try {
@@ -482,11 +490,14 @@ abstract class ResidentRunner {
   }
 
   /// Start the app and keep the process running during its lifetime.
+  ///
+  /// Returns the exit code that we should use for the flutter tool process; 0
+  /// for success, 1 for user error (e.g. bad arguments), 2 for other failures.
   Future<int> run({
     Completer<DebugConnectionInfo> connectionInfoCompleter,
     Completer<void> appStartedCompleter,
     String route,
-    bool shouldBuild = true
+    bool shouldBuild = true,
   });
 
   Future<int> attach({
@@ -506,7 +517,7 @@ abstract class ResidentRunner {
       await _debugSaveCompilationTrace();
     await stopEchoingDeviceLog();
     await preStop();
-    return stopApp();
+    await stopApp();
   }
 
   Future<void> detach() async {
@@ -571,7 +582,7 @@ abstract class ResidentRunner {
   }
 
   Future<void> _screenshot(FlutterDevice device) async {
-    final Status status = logger.startProgress('Taking screenshot for ${device.device.name}...');
+    final Status status = logger.startProgress('Taking screenshot for ${device.device.name}...', timeout: kFastOperation);
     final File outputFile = getUniqueFile(fs.currentDirectory, 'flutter', 'png');
     try {
       if (supportsServiceProtocol && isRunningDebug) {
@@ -686,14 +697,18 @@ abstract class ResidentRunner {
   }
 
   /// If the [reloadSources] parameter is not null the 'reloadSources' service
-  /// will be registered
+  /// will be registered.
+  //
+  // Failures should be indicated by completing the future with an error, using
+  // a string as the error object, which will be used by the caller (attach())
+  // to display an error message.
   Future<void> connectToServiceProtocol({
     ReloadSources reloadSources,
     Restart restart,
     CompileExpression compileExpression,
   }) async {
     if (!debuggingOptions.debuggingEnabled)
-      return Future<void>.error('Error the service protocol is not enabled.');
+      throw 'The service protocol is not enabled.';
 
     bool viewFound = false;
     for (FlutterDevice device in flutterDevices) {
@@ -704,13 +719,15 @@ abstract class ResidentRunner {
       );
       await device.getVMs();
       await device.refreshViews();
-      if (device.views.isEmpty)
-        printStatus('No Flutter views available on ${device.device.name}');
-      else
+      if (device.views.isNotEmpty)
         viewFound = true;
     }
-    if (!viewFound)
-      throwToolExit('No Flutter view is available');
+    if (!viewFound) {
+      if (flutterDevices.length == 1)
+        throw 'No Flutter view is available on ${flutterDevices.first.device.name}.';
+      throw 'No Flutter view is available on any device '
+            '(${flutterDevices.map<String>((FlutterDevice device) => device.device.name).join(', ')}).';
+    }
 
     // Listen for service protocol connection to close.
     for (FlutterDevice device in flutterDevices) {
@@ -861,12 +878,13 @@ abstract class ResidentRunner {
         printHelp(details: false);
       }
       terminal.singleCharMode = true;
-      terminal.onCharInput.listen(processTerminalInput);
+      terminal.keystrokes.listen(processTerminalInput);
     }
   }
 
   Future<int> waitForAppToFinish() async {
     final int exitCode = await _finished.future;
+    assert(exitCode != null);
     await cleanupAtFinish();
     return exitCode;
   }
@@ -887,8 +905,10 @@ abstract class ResidentRunner {
   Future<void> preStop() async { }
 
   Future<void> stopApp() async {
+    final List<Future<void>> futures = <Future<void>>[];
     for (FlutterDevice device in flutterDevices)
-      await device.stopApps();
+      futures.add(device.stopApps());
+    await Future.wait(futures);
     appFinished();
   }
 

packages/flutter_tools/lib/src/run_cold.dart

@@ -21,6 +21,7 @@ class ColdRunner extends ResidentRunner {
     DebuggingOptions debuggingOptions,
     bool usesTerminalUI = true,
     this.traceStartup = false,
+    this.awaitFirstFrameWhenTracing = true,
     this.applicationBinary,
     bool saveCompilationTrace = false,
     bool stayResident = true,
@@ -34,6 +35,7 @@ class ColdRunner extends ResidentRunner {
              ipv6: ipv6);
 
   final bool traceStartup;
+  final bool awaitFirstFrameWhenTracing;
   final File applicationBinary;
   bool _didAttach = false;
 
@@ -66,8 +68,14 @@ class ColdRunner extends ResidentRunner {
     }
 
     // Connect to observatory.
-    if (debuggingOptions.debuggingEnabled)
-      await connectToServiceProtocol();
+    if (debuggingOptions.debuggingEnabled) {
+      try {
+        await connectToServiceProtocol();
+      } on String catch (message) {
+        printError(message);
+        return 2;
+      }
+    }
 
     if (flutterDevices.first.observatoryUris != null) {
       // For now, only support one debugger connection.
@@ -91,13 +99,11 @@ class ColdRunner extends ResidentRunner {
       // Only trace startup for the first device.
       final FlutterDevice device = flutterDevices.first;
       if (device.vmServices != null && device.vmServices.isNotEmpty) {
-        printStatus('Downloading startup trace info for ${device.device.name}');
-        try {
-          await downloadStartupTrace(device.vmServices.first);
-        } catch (error) {
-          printError('Error downloading startup trace: $error');
-          return 2;
-        }
+        printStatus('Tracing startup on ${device.device.name}.');
+        await downloadStartupTrace(
+          device.vmServices.first,
+          awaitFirstFrame: awaitFirstFrameWhenTracing,
+        );
       }
       appFinished();
     } else if (stayResident) {
@@ -107,7 +113,7 @@ class ColdRunner extends ResidentRunner {
 
     appStartedCompleter?.complete();
 
-    if (stayResident)
+    if (stayResident && !traceStartup)
       return waitForAppToFinish();
     await cleanupAtFinish();
     return 0;

packages/flutter_tools/lib/src/run_hot.dart

@@ -176,6 +176,7 @@ class HotRunner extends ResidentRunner {
     throw 'Failed to compile $expression';
   }
 
+  // Returns the exit code of the flutter tool process, like [run].
   @override
   Future<int> attach({
     Completer<DebugConnectionInfo> connectionInfoCompleter,
@@ -260,10 +261,11 @@ class HotRunner extends ResidentRunner {
       return 0;
     }
 
+    int result = 0;
     if (stayResident)
-      return waitForAppToFinish();
+      result = await waitForAppToFinish();
     await cleanupAtFinish();
-    return 0;
+    return result;
   }
 
   @override
@@ -409,22 +411,21 @@ class HotRunner extends ResidentRunner {
       device.devFS.assetPathsToEvict.clear();
   }
 
-  Future<void> _cleanupDevFS() {
+  Future<void> _cleanupDevFS() async {
     final List<Future<void>> futures = <Future<void>>[];
     for (FlutterDevice device in flutterDevices) {
       if (device.devFS != null) {
-        // Cleanup the devFS; don't wait indefinitely, and ignore any errors.
+        // Cleanup the devFS, but don't wait indefinitely.
+        // We ignore any errors, because it's not clear what we would do anyway.
         futures.add(device.devFS.destroy()
           .timeout(const Duration(milliseconds: 250))
           .catchError((dynamic error) {
-            printTrace('$error');
+            printTrace('Ignored error while cleaning up DevFS: $error');
           }));
       }
       device.devFS = null;
     }
-    final Completer<void> completer = Completer<void>();
-    Future.wait(futures).whenComplete(() { completer.complete(null); } ); // ignore: unawaited_futures
-    return completer.future;
+    await Future.wait(futures);
   }
 
   Future<void> _launchInView(FlutterDevice device,
@@ -575,6 +576,7 @@ class HotRunner extends ResidentRunner {
       }
       final Status status = logger.startProgress(
         'Performing hot restart...',
+        timeout: kFastOperation,
         progressId: 'hot.restart',
       );
       try {
@@ -591,26 +593,45 @@ class HotRunner extends ResidentRunner {
     } else {
       final bool reloadOnTopOfSnapshot = _runningFromSnapshot;
       final String progressPrefix = reloadOnTopOfSnapshot ? 'Initializing' : 'Performing';
-      final Status status = logger.startProgress(
+      Status status = logger.startProgress(
         '$progressPrefix hot reload...',
-        progressId: 'hot.reload'
+        timeout: kFastOperation,
+        progressId: 'hot.reload',
       );
       OperationResult result;
+      bool showTime = true;
       try {
-        result = await _reloadSources(pause: pauseAfterRestart, reason: reason);
+        result = await _reloadSources(
+          pause: pauseAfterRestart,
+          reason: reason,
+          onSlow: (String message) {
+            status?.cancel();
+            status = logger.startProgress(
+              message,
+              timeout: kSlowOperation,
+              progressId: 'hot.reload',
+            );
+            showTime = false;
+          },
+        );
       } finally {
         status.cancel();
       }
-      if (result.isOk)
-        printStatus('${result.message} in ${getElapsedAsMilliseconds(timer.elapsed)}.');
+      if (result.isOk) {
+        if (showTime) {
+          printStatus('${result.message} in ${getElapsedAsMilliseconds(timer.elapsed)}.');
+        } else {
+          printStatus('${result.message}.');
+        }
+      }
       if (result.hintMessage != null)
         printStatus('\n${result.hintMessage}');
       return result;
     }
   }
 
-  Future<OperationResult> _reloadSources({ bool pause = false, String reason }) async {
-    final Map<String, String> analyticsParameters = <String, String> {};
+  Future<OperationResult> _reloadSources({ bool pause = false, String reason, void Function(String message) onSlow }) async {
+    final Map<String, String> analyticsParameters = <String, String>{};
     if (reason != null) {
       analyticsParameters[kEventReloadReasonParameterName] = reason;
     }
@@ -621,25 +642,24 @@ class HotRunner extends ResidentRunner {
       }
     }
 
-    if (!_isPaused()) {
-      printTrace('Refreshing active FlutterViews before reloading.');
-      await refreshViews();
-    }
-
     // The initial launch is from a script snapshot. When we reload from source
     // on top of a script snapshot, the first reload will be a worst case reload
     // because all of the sources will end up being dirty (library paths will
     // change from host path to a device path). Subsequent reloads will
     // not be affected, so we resume reporting reload times on the second
     // reload.
-    final bool shouldReportReloadTime = !_runningFromSnapshot;
+    bool shouldReportReloadTime = !_runningFromSnapshot;
     final Stopwatch reloadTimer = Stopwatch()..start();
 
+    if (!_isPaused()) {
+      printTrace('Refreshing active FlutterViews before reloading.');
+      await refreshViews();
+    }
+
     final Stopwatch devFSTimer = Stopwatch()..start();
     final UpdateFSReport updatedDevFS = await _updateDevFS();
     // Record time it took to synchronize to DevFS.
-    _addBenchmarkData('hotReloadDevFSSyncMilliseconds',
-        devFSTimer.elapsed.inMilliseconds);
+    _addBenchmarkData('hotReloadDevFSSyncMilliseconds', devFSTimer.elapsed.inMilliseconds);
     if (!updatedDevFS.success)
       return OperationResult(1, 'DevFS synchronization failed');
     String reloadMessage;
@@ -656,7 +676,6 @@ class HotRunner extends ResidentRunner {
           // running from snapshot to running from uploaded files.
           await device.resetAssetDirectory();
         }
-
         final Completer<DeviceReloadReport> completer = Completer<DeviceReloadReport>();
         allReportsFutures.add(completer.future);
         final List<Future<Map<String, dynamic>>> reportFutures = device.reloadSources(
@@ -672,7 +691,6 @@ class HotRunner extends ResidentRunner {
           completer.complete(DeviceReloadReport(device, reports));
         });
       }
-
       final List<DeviceReloadReport> reports = await Future.wait(allReportsFutures);
       for (DeviceReloadReport report in reports) {
         final Map<String, dynamic> reloadReport = report.reports[0];
@@ -700,29 +718,26 @@ class HotRunner extends ResidentRunner {
           reloadMessage = 'Reloaded $loadedLibraryCount of $finalLibraryCount libraries';
         }
       }
-    } on Map<String, dynamic> catch (error, st) {
-      printError('Hot reload failed: $error\n$st');
+    } on Map<String, dynamic> catch (error, stackTrace) {
+      printTrace('Hot reload failed: $error\n$stackTrace');
       final int errorCode = error['code'];
-      final String errorMessage = error['message'];
+      String errorMessage = error['message'];
       if (errorCode == Isolate.kIsolateReloadBarred) {
-        printError(
-          'Unable to hot reload application due to an unrecoverable error in '
-          'the source code. Please address the error and then use "R" to '
-          'restart the app.'
-        );
+        errorMessage = 'Unable to hot reload application due to an unrecoverable error in '
+                       'the source code. Please address the error and then use "R" to '
+                       'restart the app.\n'
+                       '$errorMessage (error code: $errorCode)';
         flutterUsage.sendEvent('hot', 'reload-barred');
         return OperationResult(errorCode, errorMessage);
       }
-
-      printError('Hot reload failed:\ncode = $errorCode\nmessage = $errorMessage\n$st');
-      return OperationResult(errorCode, errorMessage);
-    } catch (error, st) {
-      printError('Hot reload failed: $error\n$st');
+      return OperationResult(errorCode, '$errorMessage (error code: $errorCode)');
+    } catch (error, stackTrace) {
+      printTrace('Hot reload failed: $error\n$stackTrace');
       return OperationResult(1, '$error');
     }
     // Record time it took for the VM to reload the sources.
-    _addBenchmarkData('hotReloadVMReloadMilliseconds',
-        vmReloadTimer.elapsed.inMilliseconds);
+    _addBenchmarkData('hotReloadVMReloadMilliseconds', vmReloadTimer.elapsed.inMilliseconds);
+
     final Stopwatch reassembleTimer = Stopwatch()..start();
     // Reload the isolate.
     final List<Future<void>> allDevices = <Future<void>>[];
@@ -739,53 +754,97 @@ class HotRunner extends ResidentRunner {
       });
       allDevices.add(deviceCompleter.future);
     }
-
     await Future.wait(allDevices);
     // We are now running from source.
     _runningFromSnapshot = false;
-    // Check if the isolate is paused.
-
+    // Check if any isolates are paused.
     final List<FlutterView> reassembleViews = <FlutterView>[];
+    String serviceEventKind;
+    int pausedIsolatesFound = 0;
     for (FlutterDevice device in flutterDevices) {
       for (FlutterView view in device.views) {
         // Check if the isolate is paused, and if so, don't reassemble. Ignore the
         // PostPauseEvent event - the client requesting the pause will resume the app.
         final ServiceEvent pauseEvent = view.uiIsolate.pauseEvent;
         if (pauseEvent != null && pauseEvent.isPauseEvent && pauseEvent.kind != ServiceEvent.kPausePostRequest) {
-          continue;
+          pausedIsolatesFound += 1;
+          if (serviceEventKind == null) {
+            serviceEventKind = pauseEvent.kind;
+          } else if (serviceEventKind != pauseEvent.kind) {
+            serviceEventKind = ''; // many kinds
+          }
+        } else {
+          reassembleViews.add(view);
         }
-        reassembleViews.add(view);
       }
     }
-    if (reassembleViews.isEmpty) {
-      printTrace('Skipping reassemble because all isolates are paused.');
-      return OperationResult(OperationResult.ok.code, reloadMessage);
+    if (pausedIsolatesFound > 0) {
+      if (onSlow != null)
+        onSlow('${_describePausedIsolates(pausedIsolatesFound, serviceEventKind)}; interface might not update.');
+      if (reassembleViews.isEmpty) {
+        printTrace('Skipping reassemble because all isolates are paused.');
+        return OperationResult(OperationResult.ok.code, reloadMessage);
+      }
     }
+    assert(reassembleViews.isNotEmpty);
     printTrace('Evicting dirty assets');
     await _evictDirtyAssets();
     printTrace('Reassembling application');
-    bool reassembleAndScheduleErrors = false;
-    bool reassembleTimedOut = false;
+    bool failedReassemble = false;
     final List<Future<void>> futures = <Future<void>>[];
     for (FlutterView view in reassembleViews) {
-      futures.add(view.uiIsolate.flutterReassemble().then((_) {
-        return view.uiIsolate.uiWindowScheduleFrame();
-      }).catchError((dynamic error) {
-        if (error is TimeoutException) {
-          reassembleTimedOut = true;
-          printTrace('Reassembling ${view.uiIsolate.name} took too long.');
-          printStatus('Hot reloading ${view.uiIsolate.name} took too long; the reload may have failed.');
-        } else {
-          reassembleAndScheduleErrors = true;
+      futures.add(() async {
+        try {
+          await view.uiIsolate.flutterReassemble();
+        } catch (error) {
+          failedReassemble = true;
           printError('Reassembling ${view.uiIsolate.name} failed: $error');
+          return;
         }
-      }));
-    }
-    await Future.wait(futures);
-
+        try {
+          await view.uiIsolate.uiWindowScheduleFrame();
+        } catch (error) {
+          failedReassemble = true;
+          printError('Scheduling a frame for ${view.uiIsolate.name} failed: $error');
+        }
+      }());
+    }
+    final Future<void> reassembleFuture = Future.wait<void>(futures).then<void>((List<void> values) { });
+    await reassembleFuture.timeout(
+      const Duration(seconds: 2),
+      onTimeout: () async {
+        if (pausedIsolatesFound > 0) {
+          shouldReportReloadTime = false;
+          return; // probably no point waiting, they're probably deadlocked and we've already warned.
+        }
+        // Check if any isolate is newly paused.
+        printTrace('This is taking a long time; will now check for paused isolates.');
+        int postReloadPausedIsolatesFound = 0;
+        String serviceEventKind;
+        for (FlutterView view in reassembleViews) {
+          await view.uiIsolate.reload();
+          final ServiceEvent pauseEvent = view.uiIsolate.pauseEvent;
+          if (pauseEvent != null && pauseEvent.isPauseEvent) {
+            postReloadPausedIsolatesFound += 1;
+            if (serviceEventKind == null) {
+              serviceEventKind = pauseEvent.kind;
+            } else if (serviceEventKind != pauseEvent.kind) {
+              serviceEventKind = ''; // many kinds
+            }
+          }
+        }
+        printTrace('Found $postReloadPausedIsolatesFound newly paused isolate(s).');
+        if (postReloadPausedIsolatesFound == 0) {
+          await reassembleFuture; // must just be taking a long time... keep waiting!
+          return;
+        }
+        shouldReportReloadTime = false;
+        if (onSlow != null)
+          onSlow('${_describePausedIsolates(postReloadPausedIsolatesFound, serviceEventKind)}.');
+      },
+    );
     // Record time it took for Flutter to reassemble the application.
-    _addBenchmarkData('hotReloadFlutterReassembleMilliseconds',
-        reassembleTimer.elapsed.inMilliseconds);
+    _addBenchmarkData('hotReloadFlutterReassembleMilliseconds', reassembleTimer.elapsed.inMilliseconds);
 
     reloadTimer.stop();
     final Duration reloadDuration = reloadTimer.elapsed;
@@ -794,23 +853,51 @@ class HotRunner extends ResidentRunner {
     analyticsParameters[kEventReloadOverallTimeInMs] = '$reloadInMs';
     flutterUsage.sendEvent('hot', 'reload', parameters: analyticsParameters);
 
-    printTrace('Hot reload performed in $reloadInMs.');
-    // Record complete time it took for the reload.
-    _addBenchmarkData('hotReloadMillisecondsToFrame', reloadInMs);
-    // Only report timings if we reloaded a single view without any
-    // errors or timeouts.
-    if ((reassembleViews.length == 1) &&
-        !reassembleAndScheduleErrors &&
-        !reassembleTimedOut &&
-        shouldReportReloadTime)
+    if (shouldReportReloadTime) {
+      printTrace('Hot reload performed in ${getElapsedAsMilliseconds(reloadDuration)}.');
+      // Record complete time it took for the reload.
+      _addBenchmarkData('hotReloadMillisecondsToFrame', reloadInMs);
+    }
+    // Only report timings if we reloaded a single view without any errors.
+    if ((reassembleViews.length == 1) && !failedReassemble && shouldReportReloadTime)
       flutterUsage.sendTiming('hot', 'reload', reloadDuration);
 
     return OperationResult(
-      reassembleAndScheduleErrors ? 1 : OperationResult.ok.code,
+      failedReassemble ? 1 : OperationResult.ok.code,
       reloadMessage,
     );
   }
 
+  String _describePausedIsolates(int pausedIsolatesFound, String serviceEventKind) {
+    assert(pausedIsolatesFound > 0);
+    final StringBuffer message = StringBuffer();
+    bool plural;
+    if (pausedIsolatesFound == 1) {
+      if (flutterDevices.length == 1 && flutterDevices.single.views.length == 1) {
+        message.write('The application is ');
+      } else {
+        message.write('An isolate is ');
+      }
+      plural = false;
+    } else {
+      message.write('$pausedIsolatesFound isolates are ');
+      plural = true;
+    }
+    assert(serviceEventKind != null);
+    switch (serviceEventKind) {
+      case ServiceEvent.kPauseStart: message.write('paused (probably due to --start-paused)'); break;
+      case ServiceEvent.kPauseExit: message.write('paused because ${ plural ? 'they have' : 'it has' } terminated'); break;
+      case ServiceEvent.kPauseBreakpoint: message.write('paused in the debugger on a breakpoint'); break;
+      case ServiceEvent.kPauseInterrupted: message.write('paused due in the debugger'); break;
+      case ServiceEvent.kPauseException: message.write('paused in the debugger after an exception was thrown'); break;
+      case ServiceEvent.kPausePostRequest: message.write('paused'); break;
+      case '': message.write('paused for various reasons'); break;
+      default:
+        message.write('paused');
+    }
+    return message.toString();
+  }
+
   bool _isPaused() {
     for (FlutterDevice device in flutterDevices) {
       for (FlutterView view in device.views) {
@@ -822,7 +909,6 @@ class HotRunner extends ResidentRunner {
         }
       }
     }
-
     return false;
   }
 

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -482,19 +482,18 @@ abstract class FlutterCommand extends Command<void> {
       body: () async {
         if (flutterUsage.isFirstRun)
           flutterUsage.printWelcome();
-
+        final String commandPath = await usagePath;
         FlutterCommandResult commandResult;
         try {
-          commandResult = await verifyThenRunCommand();
+          commandResult = await verifyThenRunCommand(commandPath);
         } on ToolExit {
           commandResult = const FlutterCommandResult(ExitStatus.fail);
           rethrow;
         } finally {
           final DateTime endTime = systemClock.now();
           printTrace(userMessages.flutterElapsedTime(name, getElapsedAsMilliseconds(endTime.difference(startTime))));
-          // This is checking the result of the call to 'usagePath'
-          // (a Future<String>), and not the result of evaluating the Future.
-          if (usagePath != null) {
+          printTrace('"flutter $name" took ${getElapsedAsMilliseconds(endTime.difference(startTime))}.');
+          if (commandPath != null) {
             final List<String> labels = <String>[];
             if (commandResult?.exitStatus != null)
               labels.add(getEnumName(commandResult.exitStatus));
@@ -528,7 +527,7 @@ abstract class FlutterCommand extends Command<void> {
   /// then call this method to execute the command
   /// rather than calling [runCommand] directly.
   @mustCallSuper
-  Future<FlutterCommandResult> verifyThenRunCommand() async {
+  Future<FlutterCommandResult> verifyThenRunCommand(String commandPath) async {
     await validateCommand();
 
     // Populate the cache. We call this before pub get below so that the sky_engine
@@ -544,8 +543,6 @@ abstract class FlutterCommand extends Command<void> {
 
     setupApplicationPackages();
 
-    final String commandPath = await usagePath;
-
     if (commandPath != null) {
       final Map<String, String> additionalUsageValues = await usageValues;
       flutterUsage.sendCommand(commandPath, parameters: additionalUsageValues);

packages/flutter_tools/lib/src/test/coverage_collector.dart

@@ -57,13 +57,7 @@ class CoverageCollector extends TestWatcher {
         if (result == null)
           throw Exception('Failed to collect coverage.');
         data = result;
-      })
-      .timeout(
-        const Duration(minutes: 10),
-        onTimeout: () {
-          throw Exception('Timed out while collecting coverage.');
-        },
-      );
+      });
     await Future.any<void>(<Future<void>>[ processComplete, collectionComplete ]);
     assert(data != null);
 
@@ -77,12 +71,8 @@ class CoverageCollector extends TestWatcher {
   ///
   /// This will not start any collection tasks. It us up to the caller of to
   /// call [collectCoverage] for each process first.
-  ///
-  /// If [timeout] is specified, the future will timeout (with a
-  /// [TimeoutException]) after the specified duration.
   Future<String> finalizeCoverage({
     coverage.Formatter formatter,
-    Duration timeout,
     Directory coverageDirectory,
   }) async {
     printTrace('formating coverage data');
@@ -102,9 +92,8 @@ class CoverageCollector extends TestWatcher {
   }
 
   Future<bool> collectCoverageData(String coveragePath, { bool mergeCoverageData = false, Directory coverageDirectory }) async {
-    final Status status = logger.startProgress('Collecting coverage information...');
+    final Status status = logger.startProgress('Collecting coverage information...', timeout: kFastOperation);
     final String coverageData = await finalizeCoverage(
-      timeout: const Duration(seconds: 30),
       coverageDirectory: coverageDirectory,
     );
     status.stop();

packages/flutter_tools/lib/src/test/flutter_platform.dart

@@ -33,11 +33,17 @@ import 'watcher.dart';
 
 /// The timeout we give the test process to connect to the test harness
 /// once the process has entered its main method.
-const Duration _kTestStartupTimeout = Duration(minutes: 1);
+///
+/// We time out test execution because we expect some tests to hang and we want
+/// to know which test hung, rather than have the entire test harness just do
+/// nothing for a few hours until the user (or CI environment) gets bored.
+const Duration _kTestStartupTimeout = Duration(minutes: 5);
 
 /// The timeout we give the test process to start executing Dart code. When the
 /// CPU is under severe load, this can take a while, but it's not indicative of
 /// any problem with Flutter, so we give it a large timeout.
+///
+/// See comment under [_kTestStartupTimeout] regarding timeouts.
 const Duration _kTestProcessTimeout = Duration(minutes: 5);
 
 /// Message logged by the test process to signal that its main method has begun
@@ -288,13 +294,11 @@ class _Compiler {
             firstCompile = true;
           }
           suppressOutput = false;
-          final CompilerOutput compilerOutput = await handleTimeout<CompilerOutput>(
-            compiler.recompile(
-              request.path,
-              <String>[request.path],
-              outputPath: outputDill.path),
-              request.path,
-            );
+          final CompilerOutput compilerOutput = await compiler.recompile(
+            request.path,
+            <String>[request.path],
+            outputPath: outputDill.path,
+          );
           final String outputPath = compilerOutput?.outputFilename;
 
           // In case compiler didn't produce output or reported compilation
@@ -337,7 +341,7 @@ class _Compiler {
   Future<String> compile(String mainDart) {
     final Completer<String> completer = Completer<String>();
     compilerController.add(_CompilationRequest(mainDart, completer));
-    return handleTimeout<String>(completer.future, mainDart);
+    return completer.future;
   }
 
   Future<void> _shutdown() async {
@@ -353,13 +357,6 @@ class _Compiler {
     await _shutdown();
     await compilerController.close();
   }
-
-  static Future<T> handleTimeout<T>(Future<T> value, String path) {
-    return value.timeout(const Duration(minutes: 5), onTimeout: () {
-      printError('Compilation of $path timed out after 5 minutes.');
-      return null;
-    });
-  }
 }
 
 class _FlutterPlatform extends PlatformPlugin {

packages/flutter_tools/lib/src/tracing.dart

@@ -5,6 +5,7 @@
 import 'dart:async';
 
 import 'base/file_system.dart';
+import 'base/logger.dart';
 import 'base/utils.dart';
 import 'build_info.dart';
 import 'globals.dart';
@@ -18,6 +19,8 @@ const String _kFirstUsefulFrameEventName = 'Widgets completed first useful frame
 class Tracing {
   Tracing(this.vmService);
 
+  static const String firstUsefulFrameEventName = _kFirstUsefulFrameEventName;
+
   static Future<Tracing> connect(Uri uri) async {
     final VMService observatory = await VMService.connect(uri);
     return Tracing(observatory);
@@ -32,49 +35,46 @@ class Tracing {
 
   /// Stops tracing; optionally wait for first frame.
   Future<Map<String, dynamic>> stopTracingAndDownloadTimeline({
-    bool waitForFirstFrame = false
+    bool awaitFirstFrame = false
   }) async {
-    Map<String, dynamic> timeline;
-
-    if (!waitForFirstFrame) {
-      // Stop tracing immediately and get the timeline
-      await vmService.vm.setVMTimelineFlags(<String>[]);
-      timeline = await vmService.vm.getVMTimeline();
-    } else {
-      final Completer<void> whenFirstFrameRendered = Completer<void>();
-
-      (await vmService.onTimelineEvent).listen((ServiceEvent timelineEvent) {
-        final List<Map<String, dynamic>> events = timelineEvent.timelineEvents;
-        for (Map<String, dynamic> event in events) {
-          if (event['name'] == _kFirstUsefulFrameEventName)
-            whenFirstFrameRendered.complete();
-        }
-      });
-
-      await whenFirstFrameRendered.future.timeout(
-          const Duration(seconds: 10),
-          onTimeout: () {
-            printError(
-                'Timed out waiting for the first frame event. Either the '
-                    'application failed to start, or the event was missed because '
-                    '"flutter run" took too long to subscribe to timeline events.'
-            );
-            return null;
-          }
+    if (awaitFirstFrame) {
+      final Status status = logger.startProgress(
+        'Waiting for application to render first frame...',
+        timeout: kFastOperation,
       );
-
-      timeline = await vmService.vm.getVMTimeline();
-
-      await vmService.vm.setVMTimelineFlags(<String>[]);
+      try {
+        final Completer<void> whenFirstFrameRendered = Completer<void>();
+        (await vmService.onTimelineEvent).listen((ServiceEvent timelineEvent) {
+          final List<Map<String, dynamic>> events = timelineEvent.timelineEvents;
+          for (Map<String, dynamic> event in events) {
+            if (event['name'] == _kFirstUsefulFrameEventName)
+              whenFirstFrameRendered.complete();
+          }
+        });
+        bool done = false;
+        for (FlutterView view in vmService.vm.views) {
+          if (await view.uiIsolate.flutterAlreadyPaintedFirstUsefulFrame()) {
+            done = true;
+            break;
+          }
+        }
+        if (!done)
+          await whenFirstFrameRendered.future;
+      } catch (exception) {
+        status.cancel();
+        rethrow;
+      }
+      status.stop();
     }
-
+    final Map<String, dynamic> timeline = await vmService.vm.getVMTimeline();
+    await vmService.vm.setVMTimelineFlags(<String>[]);
     return timeline;
   }
 }
 
 /// Download the startup trace information from the given observatory client and
 /// store it to build/start_up_info.json.
-Future<void> downloadStartupTrace(VMService observatory) async {
+Future<void> downloadStartupTrace(VMService observatory, { bool awaitFirstFrame = true }) async {
   final String traceInfoFilePath = fs.path.join(getBuildDirectory(), 'start_up_info.json');
   final File traceInfoFile = fs.file(traceInfoFilePath);
 
@@ -89,45 +89,53 @@ Future<void> downloadStartupTrace(VMService observatory) async {
   final Tracing tracing = Tracing(observatory);
 
   final Map<String, dynamic> timeline = await tracing.stopTracingAndDownloadTimeline(
-      waitForFirstFrame: true
+    awaitFirstFrame: awaitFirstFrame,
   );
 
   int extractInstantEventTimestamp(String eventName) {
     final List<Map<String, dynamic>> events =
         List<Map<String, dynamic>>.from(timeline['traceEvents']);
     final Map<String, dynamic> event = events.firstWhere(
-            (Map<String, dynamic> event) => event['name'] == eventName, orElse: () => null
+      (Map<String, dynamic> event) => event['name'] == eventName, orElse: () => null
     );
     return event == null ? null : event['ts'];
   }
 
+  String message = 'No useful metrics were gathered.';
+
   final int engineEnterTimestampMicros = extractInstantEventTimestamp(_kFlutterEngineMainEnterEventName);
   final int frameworkInitTimestampMicros = extractInstantEventTimestamp(_kFrameworkInitEventName);
-  final int firstFrameTimestampMicros = extractInstantEventTimestamp(_kFirstUsefulFrameEventName);
 
   if (engineEnterTimestampMicros == null) {
     printTrace('Engine start event is missing in the timeline: $timeline');
     throw 'Engine start event is missing in the timeline. Cannot compute startup time.';
   }
 
-  if (firstFrameTimestampMicros == null) {
-    printTrace('First frame event is missing in the timeline: $timeline');
-    throw 'First frame event is missing in the timeline. Cannot compute startup time.';
-  }
-
-  final int timeToFirstFrameMicros = firstFrameTimestampMicros - engineEnterTimestampMicros;
   final Map<String, dynamic> traceInfo = <String, dynamic>{
     'engineEnterTimestampMicros': engineEnterTimestampMicros,
-    'timeToFirstFrameMicros': timeToFirstFrameMicros,
   };
 
   if (frameworkInitTimestampMicros != null) {
-    traceInfo['timeToFrameworkInitMicros'] = frameworkInitTimestampMicros - engineEnterTimestampMicros;
-    traceInfo['timeAfterFrameworkInitMicros'] = firstFrameTimestampMicros - frameworkInitTimestampMicros;
+    final int timeToFrameworkInitMicros = frameworkInitTimestampMicros - engineEnterTimestampMicros;
+    traceInfo['timeToFrameworkInitMicros'] = timeToFrameworkInitMicros;
+    message = 'Time to framework init: ${timeToFrameworkInitMicros ~/ 1000}ms.';
+  }
+
+  if (awaitFirstFrame) {
+    final int firstFrameTimestampMicros = extractInstantEventTimestamp(_kFirstUsefulFrameEventName);
+    if (firstFrameTimestampMicros == null) {
+      printTrace('First frame event is missing in the timeline: $timeline');
+      throw 'First frame event is missing in the timeline. Cannot compute startup time.';
+    }
+    final int timeToFirstFrameMicros = firstFrameTimestampMicros - engineEnterTimestampMicros;
+    traceInfo['timeToFirstFrameMicros'] = timeToFirstFrameMicros;
+    message = 'Time to first frame: ${timeToFirstFrameMicros ~/ 1000}ms.';
+    if (frameworkInitTimestampMicros != null)
+      traceInfo['timeAfterFrameworkInitMicros'] = firstFrameTimestampMicros - frameworkInitTimestampMicros;
   }
 
   traceInfoFile.writeAsStringSync(toPrettyJson(traceInfo));
 
-  printStatus('Time to first frame: ${timeToFirstFrameMicros ~/ 1000}ms.');
+  printStatus(message);
   printStatus('Saved startup trace info in ${traceInfoFile.path}.');
 }

packages/flutter_tools/lib/src/vmservice.dart

@@ -15,12 +15,17 @@ import 'package:web_socket_channel/io.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
 
 import 'base/common.dart';
+import 'base/context.dart';
 import 'base/file_system.dart';
 import 'base/io.dart' as io;
 import 'base/utils.dart';
 import 'globals.dart';
 import 'vmservice_record_replay.dart';
 
+/// Override `WebSocketConnector` in [context] to use a different constructor
+/// for [WebSocket]s (used by tests).
+typedef WebSocketConnector = Future<io.WebSocket> Function(String url);
+
 /// A function that opens a two-way communication channel to the specified [uri].
 typedef _OpenChannel = Future<StreamChannel<String>> Function(Uri uri);
 
@@ -58,60 +63,46 @@ typedef CompileExpression = Future<String> Function(
 const String _kRecordingType = 'vmservice';
 
 Future<StreamChannel<String>> _defaultOpenChannel(Uri uri) async {
-  const int _kMaxAttempts = 5;
   Duration delay = const Duration(milliseconds: 100);
   int attempts = 0;
   io.WebSocket socket;
 
-  Future<void> onError(dynamic e) async {
-    printTrace('Exception attempting to connect to observatory: $e');
+  Future<void> handleError(dynamic e) async {
+    printTrace('Exception attempting to connect to Observatory: $e');
     printTrace('This was attempt #$attempts. Will retry in $delay.');
 
+    if (attempts == 10)
+      printStatus('This is taking longer than expected...');
+
     // Delay next attempt.
     await Future<void>.delayed(delay);
 
-    // Back off exponentially.
-    delay *= 2;
+    // Back off exponentially, up to 1600ms per attempt.
+    if (delay < const Duration(seconds: 1))
+      delay *= 2;
   }
 
-  while (attempts < _kMaxAttempts && socket == null) {
+  final WebSocketConnector constructor = context[WebSocketConnector] ?? io.WebSocket.connect;
+  while (socket == null) {
     attempts += 1;
     try {
-      socket = await io.WebSocket.connect(uri.toString());
+      socket = await constructor(uri.toString());
     } on io.WebSocketException catch (e) {
-      await onError(e);
+      await handleError(e);
     } on io.SocketException catch (e) {
-      await onError(e);
+      await handleError(e);
     }
   }
-
-  if (socket == null) {
-    throw ToolExit(
-      'Attempted to connect to Dart observatory $_kMaxAttempts times, and '
-      'all attempts failed. Giving up. The URL was $uri'
-    );
-  }
-
   return IOWebSocketChannel(socket).cast<String>();
 }
 
-/// The default VM service request timeout.
-const Duration kDefaultRequestTimeout = Duration(seconds: 30);
-
-/// Used for RPC requests that may take a long time.
-const Duration kLongRequestTimeout = Duration(minutes: 1);
-
-/// Used for RPC requests that should never take a long time.
-const Duration kShortRequestTimeout = Duration(seconds: 5);
-
-// TODO(mklim): Test this, flutter/flutter#23031.
 /// A connection to the Dart VM Service.
+// TODO(mklim): Test this, https://github.com/flutter/flutter/issues/23031
 class VMService {
   VMService(
     this._peer,
     this.httpAddress,
     this.wsAddress,
-    this._requestTimeout,
     ReloadSources reloadSources,
     Restart restart,
     CompileExpression compileExpression,
@@ -247,9 +238,6 @@ class VMService {
 
   /// Connect to a Dart VM Service at [httpUri].
   ///
-  /// Requests made via the returned [VMService] time out after [requestTimeout]
-  /// amount of time, which is [kDefaultRequestTimeout] by default.
-  ///
   /// If the [reloadSources] parameter is not null, the 'reloadSources' service
   /// will be registered. The VM Service Protocol allows clients to register
   /// custom services that can be invoked by other clients through the service
@@ -258,7 +246,6 @@ class VMService {
   /// See: https://github.com/dart-lang/sdk/commit/df8bf384eb815cf38450cb50a0f4b62230fba217
   static Future<VMService> connect(
     Uri httpUri, {
-    Duration requestTimeout = kDefaultRequestTimeout,
     ReloadSources reloadSources,
     Restart restart,
     CompileExpression compileExpression,
@@ -266,7 +253,7 @@ class VMService {
     final Uri wsUri = httpUri.replace(scheme: 'ws', path: fs.path.join(httpUri.path, 'ws'));
     final StreamChannel<String> channel = await _openChannel(wsUri);
     final rpc.Peer peer = rpc.Peer.withoutJson(jsonDocument.bind(channel));
-    final VMService service = VMService(peer, httpUri, wsUri, requestTimeout, reloadSources, restart, compileExpression);
+    final VMService service = VMService(peer, httpUri, wsUri, reloadSources, restart, compileExpression);
     // This call is to ensure we are able to establish a connection instead of
     // keeping on trucking and failing farther down the process.
     await service._sendRequest('getVersion', const <String, dynamic>{});
@@ -276,7 +263,6 @@ class VMService {
   final Uri httpAddress;
   final Uri wsAddress;
   final rpc.Peer _peer;
-  final Duration _requestTimeout;
   final Completer<Map<String, dynamic>> _connectionError = Completer<Map<String, dynamic>>();
 
   VM _vm;
@@ -841,28 +827,15 @@ class VM extends ServiceObjectOwner {
   }
 
   /// Invoke the RPC and return the raw response.
-  ///
-  /// If `timeoutFatal` is false, then a timeout will result in a null return
-  /// value. Otherwise, it results in an exception.
   Future<Map<String, dynamic>> invokeRpcRaw(String method, {
     Map<String, dynamic> params = const <String, dynamic>{},
-    Duration timeout,
-    bool timeoutFatal = true,
   }) async {
     printTrace('Sending to VM service: $method($params)');
     assert(params != null);
-    timeout ??= _vmService._requestTimeout;
     try {
-      final Map<String, dynamic> result = await _vmService
-          ._sendRequest(method, params)
-          .timeout(timeout);
+      final Map<String, dynamic> result = await _vmService._sendRequest(method, params);
       printTrace('Result: ${_truncate(result.toString(), 250, '...')}');
       return result;
-    } on TimeoutException {
-      printTrace('Request to Dart VM Service timed out: $method($params)');
-      if (timeoutFatal)
-        throw TimeoutException('Request to Dart VM Service timed out: $method($params)');
-      return null;
     } on WebSocketChannelException catch (error) {
       throwToolExit('Error connecting to observatory: $error');
       return null;
@@ -876,12 +849,10 @@ class VM extends ServiceObjectOwner {
   /// Invoke the RPC and return a [ServiceObject] response.
   Future<T> invokeRpc<T extends ServiceObject>(String method, {
     Map<String, dynamic> params = const <String, dynamic>{},
-    Duration timeout,
   }) async {
     final Map<String, dynamic> response = await invokeRpcRaw(
       method,
       params: params,
-      timeout: timeout,
     );
     final ServiceObject serviceObject = ServiceObject._fromMap(this, response);
     if ((serviceObject != null) && (serviceObject._canCache)) {
@@ -968,7 +939,7 @@ class VM extends ServiceObjectOwner {
   }
 
   Future<Map<String, dynamic>> getVMTimeline() {
-    return invokeRpcRaw('_getVMTimeline', timeout: kLongRequestTimeout);
+    return invokeRpcRaw('_getVMTimeline');
   }
 
   Future<void> refreshViews({ bool waitForViews = false }) async {
@@ -982,10 +953,7 @@ class VM extends ServiceObjectOwner {
       // When the future returned by invokeRpc() below returns,
       // the _viewCache will have been updated.
       // This message updates all the views of every isolate.
-      await vmService.vm.invokeRpc<ServiceObject>(
-        '_flutter.listViews',
-        timeout: kLongRequestTimeout,
-      );
+      await vmService.vm.invokeRpc<ServiceObject>('_flutter.listViews');
       if (_viewCache.values.isNotEmpty || !waitForViews)
         return;
       failCount += 1;
@@ -1124,8 +1092,6 @@ class Isolate extends ServiceObjectOwner {
   /// Invoke the RPC and return the raw response.
   Future<Map<String, dynamic>> invokeRpcRaw(String method, {
     Map<String, dynamic> params,
-    Duration timeout,
-    bool timeoutFatal = true,
   }) {
     // Inject the 'isolateId' parameter.
     if (params == null) {
@@ -1135,7 +1101,7 @@ class Isolate extends ServiceObjectOwner {
     } else {
       params['isolateId'] = id;
     }
-    return vm.invokeRpcRaw(method, params: params, timeout: timeout, timeoutFatal: timeoutFatal);
+    return vm.invokeRpcRaw(method, params: params);
   }
 
   /// Invoke the RPC and return a ServiceObject response.
@@ -1257,40 +1223,36 @@ class Isolate extends ServiceObjectOwner {
   Future<Map<String, dynamic>> invokeFlutterExtensionRpcRaw(
     String method, {
       Map<String, dynamic> params,
-      Duration timeout,
-      bool timeoutFatal = true,
     }
-  ) {
-    return invokeRpcRaw(method, params: params, timeout: timeout,
-        timeoutFatal: timeoutFatal).catchError((dynamic error) {
-            if (error is rpc.RpcException) {
-              // If an application is not using the framework
-              if (error.code == rpc_error_code.METHOD_NOT_FOUND)
-                return null;
-              throw error;
-            }});
+  ) async {
+    try {
+      return await invokeRpcRaw(method, params: params);
+    } on rpc.RpcException catch (e) {
+      // If an application is not using the framework
+      if (e.code == rpc_error_code.METHOD_NOT_FOUND)
+        return null;
+      rethrow;
+    }
   }
 
-  // Debug dump extension methods.
-
   Future<Map<String, dynamic>> flutterDebugDumpApp() {
-    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpApp', timeout: kLongRequestTimeout);
+    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpApp');
   }
 
   Future<Map<String, dynamic>> flutterDebugDumpRenderTree() {
-    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpRenderTree', timeout: kLongRequestTimeout);
+    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpRenderTree');
   }
 
   Future<Map<String, dynamic>> flutterDebugDumpLayerTree() {
-    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpLayerTree', timeout: kLongRequestTimeout);
+    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpLayerTree');
   }
 
   Future<Map<String, dynamic>> flutterDebugDumpSemanticsTreeInTraversalOrder() {
-    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpSemanticsTreeInTraversalOrder', timeout: kLongRequestTimeout);
+    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpSemanticsTreeInTraversalOrder');
   }
 
   Future<Map<String, dynamic>> flutterDebugDumpSemanticsTreeInInverseHitTestOrder() {
-    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpSemanticsTreeInInverseHitTestOrder', timeout: kLongRequestTimeout);
+    return invokeFlutterExtensionRpcRaw('ext.flutter.debugDumpSemanticsTreeInInverseHitTestOrder');
   }
 
   Future<Map<String, dynamic>> _flutterToggle(String name) async {
@@ -1299,8 +1261,6 @@ class Isolate extends ServiceObjectOwner {
       state = await invokeFlutterExtensionRpcRaw(
         'ext.flutter.$name',
         params: <String, dynamic>{ 'enabled': state['enabled'] == 'true' ? 'false' : 'true' },
-        timeout: const Duration(milliseconds: 150),
-        timeoutFatal: false,
       );
     }
     return state;
@@ -1312,22 +1272,20 @@ class Isolate extends ServiceObjectOwner {
 
   Future<Map<String, dynamic>> flutterToggleWidgetInspector() => _flutterToggle('inspector.show');
 
-  Future<void> flutterDebugAllowBanner(bool show) async {
-    await invokeFlutterExtensionRpcRaw(
+  Future<Map<String, dynamic>> flutterDebugAllowBanner(bool show) {
+    return invokeFlutterExtensionRpcRaw(
       'ext.flutter.debugAllowBanner',
       params: <String, dynamic>{ 'enabled': show ? 'true' : 'false' },
-      timeout: const Duration(milliseconds: 150),
-      timeoutFatal: false,
     );
   }
 
-  // Reload related extension methods.
   Future<Map<String, dynamic>> flutterReassemble() {
-    return invokeFlutterExtensionRpcRaw(
-      'ext.flutter.reassemble',
-      timeout: kShortRequestTimeout,
-      timeoutFatal: true,
-    );
+    return invokeFlutterExtensionRpcRaw('ext.flutter.reassemble');
+  }
+
+  Future<bool> flutterAlreadyPaintedFirstUsefulFrame() async {
+    final Map<String, dynamic> result = await invokeFlutterExtensionRpcRaw('ext.flutter.didSendFirstFrameEvent');
+    return result['enabled'] == 'true';
   }
 
   Future<Map<String, dynamic>> uiWindowScheduleFrame() {
@@ -1335,7 +1293,8 @@ class Isolate extends ServiceObjectOwner {
   }
 
   Future<Map<String, dynamic>> flutterEvictAsset(String assetPath) {
-    return invokeFlutterExtensionRpcRaw('ext.flutter.evict',
+    return invokeFlutterExtensionRpcRaw(
+      'ext.flutter.evict',
       params: <String, dynamic>{
         'value': assetPath,
       }
@@ -1352,19 +1311,13 @@ class Isolate extends ServiceObjectOwner {
 
   // Application control extension methods.
   Future<Map<String, dynamic>> flutterExit() {
-    return invokeFlutterExtensionRpcRaw(
-      'ext.flutter.exit',
-      timeout: const Duration(seconds: 2),
-      timeoutFatal: false,
-    );
+    return invokeFlutterExtensionRpcRaw('ext.flutter.exit');
   }
 
   Future<String> flutterPlatformOverride([String platform]) async {
     final Map<String, dynamic> result = await invokeFlutterExtensionRpcRaw(
       'ext.flutter.platformOverride',
       params: platform != null ? <String, dynamic>{ 'value': platform } : <String, String>{},
-      timeout: const Duration(seconds: 5),
-      timeoutFatal: false,
     );
     if (result != null && result['value'] is String)
       return result['value'];

packages/flutter_tools/lib/src/vscode/vscode_validator.dart

@@ -14,7 +14,6 @@ class VsCodeValidator extends DoctorValidator {
 
   final VsCode _vsCode;
 
-
   static Iterable<DoctorValidator> get installedValidators {
     return VsCode
         .allInstalled()

packages/flutter_tools/test/base/context_test.dart

@@ -158,7 +158,7 @@ void main() {
           fallbacks: <Type, Generator>{
             int: () => int.parse(context[String]),
             String: () => '${context[double]}',
-            double: () => context[int] * 1.0,
+            double: () => (context[int] as int) * 1.0, // ignore: avoid_as
           },
         );
         try {

packages/flutter_tools/test/base/logger_test.dart

@@ -2,13 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:flutter_tools/src/base/context.dart';
 import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/base/terminal.dart';
+import 'package:quiver/testing/async.dart';
 
 import '../src/common.dart';
 import '../src/context.dart';
@@ -64,73 +63,117 @@ void main() {
 
   group('Spinners', () {
     MockStdio mockStdio;
-    AnsiSpinner ansiSpinner;
     AnsiStatus ansiStatus;
     int called;
     const List<String> testPlatforms = <String>['linux', 'macos', 'windows', 'fuchsia'];
-    final RegExp secondDigits = RegExp(r'[^\b]\b\b\b\b\b[0-9]+[.][0-9]+(?:s|ms)');
+    final RegExp secondDigits = RegExp(r'[0-9,.]*[0-9]m?s');
 
     setUp(() {
       mockStdio = MockStdio();
-      ansiSpinner = AnsiSpinner();
       called = 0;
       ansiStatus = AnsiStatus(
         message: 'Hello world',
-        expectSlowOperation: true,
+        timeout: const Duration(milliseconds: 10),
         padding: 20,
-        onFinish: () => called++,
+        onFinish: () => called += 1,
       );
     });
 
     List<String> outputStdout() => mockStdio.writtenToStdout.join('').split('\n');
     List<String> outputStderr() => mockStdio.writtenToStderr.join('').split('\n');
 
-    Future<void> doWhileAsync(bool doThis()) async {
-      return Future.doWhile(() {
-        // We want to let other tasks run at the same time, so we schedule these
-        // using a timer rather than a microtask.
-        return Future<bool>.delayed(Duration.zero, doThis);
-      });
+    void doWhileAsync(FakeAsync time, bool doThis()) {
+      do {
+        time.elapse(const Duration(milliseconds: 1));
+      } while (doThis());
     }
 
     for (String testOs in testPlatforms) {
       testUsingContext('AnsiSpinner works for $testOs', () async {
-        ansiSpinner.start();
-        await doWhileAsync(() => ansiSpinner.ticks < 10);
-        List<String> lines = outputStdout();
-        expect(lines[0], startsWith(platform.isWindows
-            ? ' \b-\b\\\b|\b/\b-\b\\\b|\b/'
-            : ' \b⣾\b⣽\b⣻\b⢿\b⡿\b⣟\b⣯\b⣷\b⣾\b⣽'));
-        expect(lines[0].endsWith('\n'), isFalse);
-        expect(lines.length, equals(1));
-        ansiSpinner.stop();
-        lines = outputStdout();
-        expect(lines[0], endsWith('\b \b'));
-        expect(lines.length, equals(1));
-
-        // Verify that stopping or canceling multiple times throws.
-        expect(() {
+        bool done = false;
+        FakeAsync().run((FakeAsync time) {
+          final AnsiSpinner ansiSpinner = AnsiSpinner(
+            timeout: const Duration(hours: 10),
+          )..start();
+          doWhileAsync(time, () => ansiSpinner.ticks < 10);
+          List<String> lines = outputStdout();
+          expect(lines[0], startsWith(
+            platform.isWindows
+              ? ' \b\\\b|\b/\b-\b\\\b|\b/\b-'
+              : ' \b⣽\b⣻\b⢿\b⡿\b⣟\b⣯\b⣷\b⣾\b⣽\b⣻'
+            ),
+          );
+          expect(lines[0].endsWith('\n'), isFalse);
+          expect(lines.length, equals(1));
           ansiSpinner.stop();
-        }, throwsA(isInstanceOf<AssertionError>()));
-        expect(() {
-          ansiSpinner.cancel();
-        }, throwsA(isInstanceOf<AssertionError>()));
+          lines = outputStdout();
+          expect(lines[0], endsWith('\b \b'));
+          expect(lines.length, equals(1));
+
+          // Verify that stopping or canceling multiple times throws.
+          expect(() {
+            ansiSpinner.stop();
+          }, throwsA(isInstanceOf<AssertionError>()));
+          expect(() {
+            ansiSpinner.cancel();
+          }, throwsA(isInstanceOf<AssertionError>()));
+          done = true;
+        });
+        expect(done, isTrue);
       }, overrides: <Type, Generator>{
         Platform: () => FakePlatform(operatingSystem: testOs),
         Stdio: () => mockStdio,
       });
 
-      testUsingContext('Stdout startProgress handle null inputs on colored terminal for $testOs', () async {
-        context[Logger].startProgress(
-          null,
-          progressId: null,
-          expectSlowOperation: null,
-          progressIndicatorPadding: null,
-        );
-        final List<String> lines = outputStdout();
-        expect(outputStderr().length, equals(1));
-        expect(outputStderr().first, isEmpty);
-        expect(lines[0], matches(platform.isWindows ? r'[ ]{64} [\b]-' : r'[ ]{64} [\b]⣾'));
+      testUsingContext('AnsiSpinner works for $testOs', () async {
+        bool done = false;
+        // We pad the time here so that we have a little slack in terms of the first part of this test
+        // taking longer to run than we'd like, since we are forced to start the timer before the actual
+        // stopwatch that we're trying to test. This is an unfortunate possible race condition. If this
+        // turns out to be flaky, we will need to find another solution.
+        final Future<void> tenMillisecondsLater = Future<void>.delayed(const Duration(milliseconds: 15));
+        await FakeAsync().run((FakeAsync time) async {
+          final AnsiSpinner ansiSpinner = AnsiSpinner(
+            timeout: const Duration(milliseconds: 10),
+          )..start();
+          doWhileAsync(time, () => ansiSpinner.ticks < 10); // one second
+          expect(ansiSpinner.seemsSlow, isFalse); // ignore: invalid_use_of_protected_member
+          expect(outputStdout().join('\n'), isNot(contains('This is taking an unexpectedly long time.')));
+          await tenMillisecondsLater;
+          doWhileAsync(time, () => ansiSpinner.ticks < 30); // three seconds
+          expect(ansiSpinner.seemsSlow, isTrue); // ignore: invalid_use_of_protected_member
+          expect(outputStdout().join('\n'), contains('This is taking an unexpectedly long time.'));
+          ansiSpinner.stop();
+          expect(outputStdout().join('\n'), isNot(contains('(!)')));
+          done = true;
+        });
+        expect(done, isTrue);
+      }, overrides: <Type, Generator>{
+        Platform: () => FakePlatform(operatingSystem: testOs),
+        Stdio: () => mockStdio,
+      });
+
+      testUsingContext('Stdout startProgress on colored terminal for $testOs', () async {
+        bool done = false;
+        FakeAsync().run((FakeAsync time) {
+          final Logger logger = context[Logger];
+          final Status status = logger.startProgress(
+            'Hello',
+            progressId: null,
+            timeout: kSlowOperation,
+            progressIndicatorPadding: 20, // this minus the "Hello" equals the 15 below.
+          );
+          expect(outputStderr().length, equals(1));
+          expect(outputStderr().first, isEmpty);
+          // the 5 below is the margin that is always included between the message and the time.
+          expect(outputStdout().join('\n'), matches(platform.isWindows ? r'^Hello {15} {5} {8}[\b]{8} {7}\\$' :
+                                                                         r'^Hello {15} {5} {8}[\b]{8} {7}⣽$'));
+          status.stop();
+          expect(outputStdout().join('\n'), matches(platform.isWindows ? r'^Hello {15} {5} {8}[\b]{8} {7}\\[\b]{8} {8}[\b]{8}[\d, ]{4}[\d]\.[\d]s[\n]$' :
+                                                                         r'^Hello {15} {5} {8}[\b]{8} {7}⣽[\b]{8} {8}[\b]{8}[\d, ]{4}[\d]\.[\d]s[\n]$'));
+          done = true;
+        });
+        expect(done, isTrue);
       }, overrides: <Type, Generator>{
         Logger: () => StdoutLogger(),
         OutputPreferences: () => OutputPreferences(showColor: true),
@@ -138,58 +181,145 @@ void main() {
         Stdio: () => mockStdio,
       });
 
+      testUsingContext('Stdout startProgress on colored terminal pauses on $testOs', () async {
+        bool done = false;
+        FakeAsync().run((FakeAsync time) {
+          final Logger logger = context[Logger];
+          final Status status = logger.startProgress(
+            'Knock Knock, Who\'s There',
+            timeout: const Duration(days: 10),
+            progressIndicatorPadding: 10,
+          );
+          logger.printStatus('Rude Interrupting Cow');
+          status.stop();
+          final String a = platform.isWindows ? '\\' : '⣽';
+          final String b = platform.isWindows ? '|' : '⣻';
+          expect(
+            outputStdout().join('\n'),
+            'Knock Knock, Who\'s There     ' // initial message
+            '        ' // placeholder so that spinner can backspace on its first tick
+            '\b\b\b\b\b\b\b\b       $a' // first tick
+            '\b\b\b\b\b\b\b\b        ' // clearing the spinner
+            '\b\b\b\b\b\b\b\b' // clearing the clearing of the spinner
+            '\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b                             ' // clearing the message
+            '\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b' // clearing the clearing of the message
+            'Rude Interrupting Cow\n' // message
+            'Knock Knock, Who\'s There     ' // message restoration
+            '        ' // placeholder so that spinner can backspace on its second tick
+            '\b\b\b\b\b\b\b\b       $b' // second tick
+            '\b\b\b\b\b\b\b\b        ' // clearing the spinner to put the time
+            '\b\b\b\b\b\b\b\b' // clearing the clearing of the spinner
+            '    0.0s\n', // replacing it with the time
+          );
+          done = true;
+        });
+        expect(done, isTrue);
+      }, overrides: <Type, Generator>{
+        Logger: () => StdoutLogger(),
+        OutputPreferences: () => OutputPreferences(showColor: true),
+        Platform: () => FakePlatform(operatingSystem: testOs)..stdoutSupportsAnsi = true,
+        Stdio: () => mockStdio,
+      });
+
+      testUsingContext('AnsiStatus works for $testOs', () async {
+        bool done = false;
+        // We pad the time here so that we have a little slack in terms of the first part of this test
+        // taking longer to run than we'd like, since we are forced to start the timer before the actual
+        // stopwatch that we're trying to test. This is an unfortunate possible race condition. If this
+        // turns out to be flaky, we will need to find another solution.
+        final Future<void> tenMillisecondsLater = Future<void>.delayed(const Duration(milliseconds: 15));
+        await FakeAsync().run((FakeAsync time) async {
+          ansiStatus.start();
+          doWhileAsync(time, () => ansiStatus.ticks < 10); // one second
+          expect(ansiStatus.seemsSlow, isFalse); // ignore: invalid_use_of_protected_member
+          expect(outputStdout().join('\n'), isNot(contains('This is taking an unexpectedly long time.')));
+          expect(outputStdout().join('\n'), isNot(contains('(!)')));
+          await tenMillisecondsLater;
+          doWhileAsync(time, () => ansiStatus.ticks < 30); // three seconds
+          expect(ansiStatus.seemsSlow, isTrue); // ignore: invalid_use_of_protected_member
+          expect(outputStdout().join('\n'), contains('This is taking an unexpectedly long time.'));
+          ansiStatus.stop();
+          expect(outputStdout().join('\n'), contains('(!)'));
+          done = true;
+        });
+        expect(done, isTrue);
+      }, overrides: <Type, Generator>{
+        Platform: () => FakePlatform(operatingSystem: testOs),
+        Stdio: () => mockStdio,
+      });
+
       testUsingContext('AnsiStatus works when cancelled for $testOs', () async {
-        ansiStatus.start();
-        await doWhileAsync(() => ansiStatus.ticks < 10);
-        List<String> lines = outputStdout();
-        expect(lines[0], startsWith(platform.isWindows
-            ? 'Hello world               \b-\b\\\b|\b/\b-\b\\\b|\b/'
-            : 'Hello world               \b⣾\b⣽\b⣻\b⢿\b⡿\b⣟\b⣯\b⣷\b⣾\b⣽'));
-        expect(lines.length, equals(1));
-        expect(lines[0].endsWith('\n'), isFalse);
-
-        // Verify a cancel does _not_ print the time and prints a newline.
-        ansiStatus.cancel();
-        lines = outputStdout();
-        final List<Match> matches = secondDigits.allMatches(lines[0]).toList();
-        expect(matches, isEmpty);
-        expect(lines[0], endsWith('\b \b'));
-        expect(called, equals(1));
-        expect(lines.length, equals(2));
-        expect(lines[1], equals(''));
-
-        // Verify that stopping or canceling multiple times throws.
-        expect(() { ansiStatus.cancel(); }, throwsA(isInstanceOf<AssertionError>()));
-        expect(() { ansiStatus.stop(); }, throwsA(isInstanceOf<AssertionError>()));
+        bool done = false;
+        FakeAsync().run((FakeAsync time) {
+          ansiStatus.start();
+          doWhileAsync(time, () => ansiStatus.ticks < 10);
+          List<String> lines = outputStdout();
+          expect(lines[0], startsWith(platform.isWindows
+              ? 'Hello world                      \b\b\b\b\b\b\b\b       \\\b\b\b\b\b\b\b\b       |\b\b\b\b\b\b\b\b       /\b\b\b\b\b\b\b\b       -\b\b\b\b\b\b\b\b       \\\b\b\b\b\b\b\b\b       |\b\b\b\b\b\b\b\b       /\b\b\b\b\b\b\b\b       -\b\b\b\b\b\b\b\b       \\\b\b\b\b\b\b\b\b       |'
+              : 'Hello world                      \b\b\b\b\b\b\b\b       ⣽\b\b\b\b\b\b\b\b       ⣻\b\b\b\b\b\b\b\b       ⢿\b\b\b\b\b\b\b\b       ⡿\b\b\b\b\b\b\b\b       ⣟\b\b\b\b\b\b\b\b       ⣯\b\b\b\b\b\b\b\b       ⣷\b\b\b\b\b\b\b\b       ⣾\b\b\b\b\b\b\b\b       ⣽\b\b\b\b\b\b\b\b       ⣻'));
+          expect(lines.length, equals(1));
+          expect(lines[0].endsWith('\n'), isFalse);
+
+          // Verify a cancel does _not_ print the time and prints a newline.
+          ansiStatus.cancel();
+          lines = outputStdout();
+          final List<Match> matches = secondDigits.allMatches(lines[0]).toList();
+          expect(matches, isEmpty);
+          final String x = platform.isWindows ? '|' : '⣻';
+          expect(lines[0], endsWith('$x\b\b\b\b\b\b\b\b        \b\b\b\b\b\b\b\b'));
+          expect(called, equals(1));
+          expect(lines.length, equals(2));
+          expect(lines[1], equals(''));
+
+          // Verify that stopping or canceling multiple times throws.
+          expect(() { ansiStatus.cancel(); }, throwsA(isInstanceOf<AssertionError>()));
+          expect(() { ansiStatus.stop(); }, throwsA(isInstanceOf<AssertionError>()));
+          done = true;
+        });
+        expect(done, isTrue);
       }, overrides: <Type, Generator>{
         Platform: () => FakePlatform(operatingSystem: testOs),
         Stdio: () => mockStdio,
       });
 
       testUsingContext('AnsiStatus works when stopped for $testOs', () async {
-        ansiStatus.start();
-        await doWhileAsync(() => ansiStatus.ticks < 10);
-        List<String> lines = outputStdout();
-        expect(lines[0], startsWith(platform.isWindows
-            ? 'Hello world               \b-\b\\\b|\b/\b-\b\\\b|\b/'
-            : 'Hello world               \b⣾\b⣽\b⣻\b⢿\b⡿\b⣟\b⣯\b⣷\b⣾\b⣽'));
-        expect(lines.length, equals(1));
-
-        // Verify a stop prints the time.
-        ansiStatus.stop();
-        lines = outputStdout();
-        final List<Match> matches = secondDigits.allMatches(lines[0]).toList();
-        expect(matches, isNotNull);
-        expect(matches, hasLength(1));
-        final Match match = matches.first;
-        expect(lines[0], endsWith(match.group(0)));
-        expect(called, equals(1));
-        expect(lines.length, equals(2));
-        expect(lines[1], equals(''));
-
-        // Verify that stopping or canceling multiple times throws.
-        expect(() { ansiStatus.stop(); }, throwsA(isInstanceOf<AssertionError>()));
-        expect(() { ansiStatus.cancel(); }, throwsA(isInstanceOf<AssertionError>()));
+        bool done = false;
+        FakeAsync().run((FakeAsync time) {
+          ansiStatus.start();
+          doWhileAsync(time, () => ansiStatus.ticks < 10);
+          List<String> lines = outputStdout();
+          expect(lines, hasLength(1));
+          expect(lines[0],
+            platform.isWindows
+              ? 'Hello world                      \b\b\b\b\b\b\b\b       \\\b\b\b\b\b\b\b\b       |\b\b\b\b\b\b\b\b       /\b\b\b\b\b\b\b\b       -\b\b\b\b\b\b\b\b       \\\b\b\b\b\b\b\b\b       |\b\b\b\b\b\b\b\b       /\b\b\b\b\b\b\b\b       -\b\b\b\b\b\b\b\b       \\\b\b\b\b\b\b\b\b       |'
+              : 'Hello world                      \b\b\b\b\b\b\b\b       ⣽\b\b\b\b\b\b\b\b       ⣻\b\b\b\b\b\b\b\b       ⢿\b\b\b\b\b\b\b\b       ⡿\b\b\b\b\b\b\b\b       ⣟\b\b\b\b\b\b\b\b       ⣯\b\b\b\b\b\b\b\b       ⣷\b\b\b\b\b\b\b\b       ⣾\b\b\b\b\b\b\b\b       ⣽\b\b\b\b\b\b\b\b       ⣻',
+          );
+
+          // Verify a stop prints the time.
+          ansiStatus.stop();
+          lines = outputStdout();
+          expect(lines, hasLength(2));
+          expect(lines[0], matches(
+            platform.isWindows
+              ? r'Hello world               {8}[\b]{8} {7}\\[\b]{8} {7}|[\b]{8} {7}/[\b]{8} {7}-[\b]{8} {7}\\[\b]{8} {7}|[\b]{8} {7}/[\b]{8} {7}-[\b]{8} {7}\\[\b]{8} {7}|[\b]{8} {7} [\b]{8}[\d., ]{6}[\d]ms$'
+              : r'Hello world               {8}[\b]{8} {7}⣽[\b]{8} {7}⣻[\b]{8} {7}⢿[\b]{8} {7}⡿[\b]{8} {7}⣟[\b]{8} {7}⣯[\b]{8} {7}⣷[\b]{8} {7}⣾[\b]{8} {7}⣽[\b]{8} {7}⣻[\b]{8} {7} [\b]{8}[\d., ]{5}[\d]ms$'
+          ));
+          expect(lines[1], isEmpty);
+          final List<Match> times = secondDigits.allMatches(lines[0]).toList();
+          expect(times, isNotNull);
+          expect(times, hasLength(1));
+          final Match match = times.single;
+          expect(lines[0], endsWith(match.group(0)));
+          expect(called, equals(1));
+          expect(lines.length, equals(2));
+          expect(lines[1], equals(''));
+
+          // Verify that stopping or canceling multiple times throws.
+          expect(() { ansiStatus.stop(); }, throwsA(isInstanceOf<AssertionError>()));
+          expect(() { ansiStatus.cancel(); }, throwsA(isInstanceOf<AssertionError>()));
+          done = true;
+        });
+        expect(done, isTrue);
       }, overrides: <Type, Generator>{
         Platform: () => FakePlatform(operatingSystem: testOs),
         Stdio: () => mockStdio,
@@ -207,7 +337,7 @@ void main() {
       called = 0;
       summaryStatus = SummaryStatus(
         message: 'Hello world',
-        expectSlowOperation: true,
+        timeout: kSlowOperation,
         padding: 20,
         onFinish: () => called++,
       );
@@ -217,7 +347,8 @@ void main() {
     List<String> outputStderr() => mockStdio.writtenToStderr.join('').split('\n');
 
     testUsingContext('Error logs are wrapped', () async {
-      context[Logger].printError('0123456789' * 15);
+      final Logger logger = context[Logger];
+      logger.printError('0123456789' * 15);
       final List<String> lines = outputStderr();
       expect(outputStdout().length, equals(1));
       expect(outputStdout().first, isEmpty);
@@ -233,7 +364,8 @@ void main() {
     });
 
     testUsingContext('Error logs are wrapped and can be indented.', () async {
-      context[Logger].printError('0123456789' * 15, indent: 5);
+      final Logger logger = context[Logger];
+      logger.printError('0123456789' * 15, indent: 5);
       final List<String> lines = outputStderr();
       expect(outputStdout().length, equals(1));
       expect(outputStdout().first, isEmpty);
@@ -252,7 +384,8 @@ void main() {
     });
 
     testUsingContext('Error logs are wrapped and can have hanging indent.', () async {
-      context[Logger].printError('0123456789' * 15, hangingIndent: 5);
+      final Logger logger = context[Logger];
+      logger.printError('0123456789' * 15, hangingIndent: 5);
       final List<String> lines = outputStderr();
       expect(outputStdout().length, equals(1));
       expect(outputStdout().first, isEmpty);
@@ -271,7 +404,8 @@ void main() {
     });
 
     testUsingContext('Error logs are wrapped, indented, and can have hanging indent.', () async {
-      context[Logger].printError('0123456789' * 15, indent: 4, hangingIndent: 5);
+      final Logger logger = context[Logger];
+      logger.printError('0123456789' * 15, indent: 4, hangingIndent: 5);
       final List<String> lines = outputStderr();
       expect(outputStdout().length, equals(1));
       expect(outputStdout().first, isEmpty);
@@ -290,7 +424,8 @@ void main() {
     });
 
     testUsingContext('Stdout logs are wrapped', () async {
-      context[Logger].printStatus('0123456789' * 15);
+      final Logger logger = context[Logger];
+      logger.printStatus('0123456789' * 15);
       final List<String> lines = outputStdout();
       expect(outputStderr().length, equals(1));
       expect(outputStderr().first, isEmpty);
@@ -306,7 +441,8 @@ void main() {
     });
 
     testUsingContext('Stdout logs are wrapped and can be indented.', () async {
-      context[Logger].printStatus('0123456789' * 15, indent: 5);
+      final Logger logger = context[Logger];
+      logger.printStatus('0123456789' * 15, indent: 5);
       final List<String> lines = outputStdout();
       expect(outputStderr().length, equals(1));
       expect(outputStderr().first, isEmpty);
@@ -325,7 +461,8 @@ void main() {
     });
 
     testUsingContext('Stdout logs are wrapped and can have hanging indent.', () async {
-      context[Logger].printStatus('0123456789' * 15, hangingIndent: 5);
+      final Logger logger = context[Logger];
+      logger.printStatus('0123456789' * 15, hangingIndent: 5);
       final List<String> lines = outputStdout();
       expect(outputStderr().length, equals(1));
       expect(outputStderr().first, isEmpty);
@@ -344,7 +481,8 @@ void main() {
     });
 
     testUsingContext('Stdout logs are wrapped, indented, and can have hanging indent.', () async {
-      context[Logger].printStatus('0123456789' * 15, indent: 4, hangingIndent: 5);
+      final Logger logger = context[Logger];
+      logger.printStatus('0123456789' * 15, indent: 4, hangingIndent: 5);
       final List<String> lines = outputStdout();
       expect(outputStderr().length, equals(1));
       expect(outputStderr().first, isEmpty);
@@ -363,7 +501,8 @@ void main() {
     });
 
     testUsingContext('Error logs are red', () async {
-      context[Logger].printError('Pants on fire!');
+      final Logger logger = context[Logger];
+      logger.printError('Pants on fire!');
       final List<String> lines = outputStderr();
       expect(outputStdout().length, equals(1));
       expect(outputStdout().first, isEmpty);
@@ -376,7 +515,8 @@ void main() {
     });
 
     testUsingContext('Stdout logs are not colored', () async {
-      context[Logger].printStatus('All good.');
+      final Logger logger = context[Logger];
+      logger.printStatus('All good.');
       final List<String> lines = outputStdout();
       expect(outputStderr().length, equals(1));
       expect(outputStderr().first, isEmpty);
@@ -388,7 +528,14 @@ void main() {
     });
 
     testUsingContext('Stdout printStatus handle null inputs on colored terminal', () async {
-      context[Logger].printStatus(null, emphasis: null, color: null, newline: null, indent: null);
+      final Logger logger = context[Logger];
+      logger.printStatus(
+        null,
+        emphasis: null,
+        color: null,
+        newline: null,
+        indent: null,
+      );
       final List<String> lines = outputStdout();
       expect(outputStderr().length, equals(1));
       expect(outputStderr().first, isEmpty);
@@ -399,8 +546,15 @@ void main() {
       Stdio: () => mockStdio,
     });
 
-    testUsingContext('Stdout printStatus handle null inputs on regular terminal', () async {
-      context[Logger].printStatus(null, emphasis: null, color: null, newline: null, indent: null);
+    testUsingContext('Stdout printStatus handle null inputs on non-color terminal', () async {
+      final Logger logger = context[Logger];
+      logger.printStatus(
+        null,
+        emphasis: null,
+        color: null,
+        newline: null,
+        indent: null,
+      );
       final List<String> lines = outputStdout();
       expect(outputStderr().length, equals(1));
       expect(outputStderr().first, isEmpty);
@@ -412,17 +566,27 @@ void main() {
       Platform: _kNoAnsiPlatform,
     });
 
-    testUsingContext('Stdout startProgress handle null inputs on regular terminal', () async {
-      context[Logger].startProgress(
-        null,
-        progressId: null,
-        expectSlowOperation: null,
-        progressIndicatorPadding: null,
-      );
-      final List<String> lines = outputStdout();
-      expect(outputStderr().length, equals(1));
-      expect(outputStderr().first, isEmpty);
-      expect(lines[0], matches('[ ]{64}'));
+    testUsingContext('Stdout startProgress on non-color terminal', () async {
+      bool done = false;
+      FakeAsync().run((FakeAsync time) {
+        final Logger logger = context[Logger];
+        final Status status = logger.startProgress(
+          'Hello',
+          progressId: null,
+          timeout: kSlowOperation,
+          progressIndicatorPadding: 20, // this minus the "Hello" equals the 15 below.
+        );
+        expect(outputStderr().length, equals(1));
+        expect(outputStderr().first, isEmpty);
+        // the 5 below is the margin that is always included between the message and the time.
+        expect(outputStdout().join('\n'), matches(platform.isWindows ? r'^Hello {15} {5}$' :
+                                                                       r'^Hello {15} {5}$'));
+        status.stop();
+        expect(outputStdout().join('\n'), matches(platform.isWindows ? r'^Hello {15} {5}[\d, ]{4}[\d]\.[\d]s[\n]$' :
+                                                                       r'^Hello {15} {5}[\d, ]{4}[\d]\.[\d]s[\n]$'));
+        done = true;
+      });
+      expect(done, isTrue);
     }, overrides: <Type, Generator>{
       Logger: () => StdoutLogger(),
       OutputPreferences: () => OutputPreferences(showColor: false),
@@ -476,11 +640,16 @@ void main() {
     }, overrides: <Type, Generator>{Stdio: () => mockStdio, Platform: _kNoAnsiPlatform});
 
     testUsingContext('sequential startProgress calls with StdoutLogger', () async {
-      context[Logger].startProgress('AAA')..stop();
-      context[Logger].startProgress('BBB')..stop();
-      expect(outputStdout().length, equals(3));
-      expect(outputStdout()[0], matches(RegExp(r'AAA[ ]{60}[\d ]{3}[\d]ms')));
-      expect(outputStdout()[1], matches(RegExp(r'BBB[ ]{60}[\d ]{3}[\d]ms')));
+      final Logger logger = context[Logger];
+      logger.startProgress('AAA', timeout: kFastOperation)..stop();
+      logger.startProgress('BBB', timeout: kFastOperation)..stop();
+      final List<String> output = outputStdout();
+      expect(output.length, equals(3));
+      // There's 61 spaces at the start: 59 (padding default) - 3 (length of AAA) + 5 (margin).
+      // Then there's a left-padded "0ms" 8 characters wide, so 5 spaces then "0ms"
+      // (except sometimes it's randomly slow so we handle up to "99,999ms").
+      expect(output[0], matches(RegExp(r'AAA[ ]{61}[\d, ]{5}[\d]ms')));
+      expect(output[1], matches(RegExp(r'BBB[ ]{61}[\d, ]{5}[\d]ms')));
     }, overrides: <Type, Generator>{
       Logger: () => StdoutLogger(),
       OutputPreferences: () => OutputPreferences(showColor: false),
@@ -489,13 +658,14 @@ void main() {
     });
 
     testUsingContext('sequential startProgress calls with VerboseLogger and StdoutLogger', () async {
-      context[Logger].startProgress('AAA')..stop();
-      context[Logger].startProgress('BBB')..stop();
+      final Logger logger = context[Logger];
+      logger.startProgress('AAA', timeout: kFastOperation)..stop();
+      logger.startProgress('BBB', timeout: kFastOperation)..stop();
       expect(outputStdout(), <Matcher>[
         matches(r'^\[ (?: {0,2}\+[0-9]{1,3} ms|       )\] AAA$'),
-        matches(r'^\[ (?: {0,2}\+[0-9]{1,3} ms|       )\] AAA \(completed\)$'),
+        matches(r'^\[ (?: {0,2}\+[0-9]{1,3} ms|       )\] AAA \(completed.*\)$'),
         matches(r'^\[ (?: {0,2}\+[0-9]{1,3} ms|       )\] BBB$'),
-        matches(r'^\[ (?: {0,2}\+[0-9]{1,3} ms|       )\] BBB \(completed\)$'),
+        matches(r'^\[ (?: {0,2}\+[0-9]{1,3} ms|       )\] BBB \(completed.*\)$'),
         matches(r'^$'),
       ]);
     }, overrides: <Type, Generator>{
@@ -505,9 +675,9 @@ void main() {
     });
 
     testUsingContext('sequential startProgress calls with BufferLogger', () async {
-      context[Logger].startProgress('AAA')..stop();
-      context[Logger].startProgress('BBB')..stop();
       final BufferLogger logger = context[Logger];
+      logger.startProgress('AAA', timeout: kFastOperation)..stop();
+      logger.startProgress('BBB', timeout: kFastOperation)..stop();
       expect(logger.statusText, 'AAA\nBBB\n');
     }, overrides: <Type, Generator>{
       Logger: () => BufferLogger(),

packages/flutter_tools/test/base/terminal_test.dart

@@ -165,7 +165,7 @@ Stream<String> mockStdInStream;
 
 class TestTerminal extends AnsiTerminal {
   @override
-  Stream<String> get onCharInput {
+  Stream<String> get keystrokes {
     return mockStdInStream;
   }
 }

packages/flutter_tools/test/commands/attach_test.dart

@@ -7,12 +7,15 @@ import 'dart:async';
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/common.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/platform.dart';
+import 'package:flutter_tools/src/base/terminal.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/attach.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/resident_runner.dart';
 import 'package:flutter_tools/src/run_hot.dart';
+import 'package:meta/meta.dart';
 import 'package:mockito/mockito.dart';
 
 import '../src/common.dart';
@@ -20,6 +23,7 @@ import '../src/context.dart';
 import '../src/mocks.dart';
 
 void main() {
+  final StreamLogger logger = StreamLogger();
   group('attach', () {
     final FileSystem testFileSystem = MemoryFileSystem(
       style: platform.isWindows ? FileSystemStyle.windows : FileSystemStyle
@@ -48,18 +52,19 @@ void main() {
           // Now that the reader is used, start writing messages to it.
           Timer.run(() {
             mockLogReader.addLine('Foo');
-            mockLogReader.addLine(
-                'Observatory listening on http://127.0.0.1:$devicePort');
+            mockLogReader.addLine('Observatory listening on http://127.0.0.1:$devicePort');
           });
 
           return mockLogReader;
         });
-        when(device.portForwarder).thenReturn(portForwarder);
+        when(device.portForwarder)
+          .thenReturn(portForwarder);
         when(portForwarder.forward(devicePort, hostPort: anyNamed('hostPort')))
-            .thenAnswer((_) async => hostPort);
-        when(portForwarder.forwardedPorts).thenReturn(
-            <ForwardedPort>[ForwardedPort(hostPort, devicePort)]);
-        when(portForwarder.unforward(any)).thenAnswer((_) async => null);
+          .thenAnswer((_) async => hostPort);
+        when(portForwarder.forwardedPorts)
+          .thenReturn(<ForwardedPort>[ForwardedPort(hostPort, devicePort)]);
+        when(portForwarder.unforward(any))
+          .thenAnswer((_) async => null);
 
         // We cannot add the device to a device manager because that is
         // only enabled by the context of each testUsingContext call.
@@ -74,16 +79,23 @@ void main() {
 
       testUsingContext('finds observatory port and forwards', () async {
         testDeviceManager.addDevice(device);
-
-        final AttachCommand command = AttachCommand();
-
-        await createTestCommandRunner(command).run(<String>['attach']);
-
+        final Completer<void> completer = Completer<void>();
+        final StreamSubscription<String> loggerSubscription = logger.stream.listen((String message) {
+          if (message == '[stdout] Done.') {
+            // The "Done." message is output by the AttachCommand when it's done.
+            completer.complete();
+          }
+        });
+        final Future<void> task = createTestCommandRunner(AttachCommand()).run(<String>['attach']);
+        await completer.future;
         verify(
           portForwarder.forward(devicePort, hostPort: anyNamed('hostPort')),
         ).called(1);
+        await expectLoggerInterruptEndsTask(task, logger);
+        await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
+        Logger: () => logger,
       });
 
       testUsingContext('accepts filesystem parameters', () async {
@@ -94,6 +106,9 @@ void main() {
         const String projectRoot = '/build-output/project-root';
         const String outputDill = '/tmp/output.dill';
 
+        final MockHotRunner mockHotRunner = MockHotRunner();
+        when(mockHotRunner.attach()).thenAnswer((_) async => 0);
+
         final MockHotRunnerFactory mockHotRunnerFactory = MockHotRunnerFactory();
         when(
           mockHotRunnerFactory.build(
@@ -106,7 +121,7 @@ void main() {
             usesTerminalUI: anyNamed('usesTerminalUI'),
             ipv6: false,
           ),
-        )..thenReturn(MockHotRunner());
+        ).thenReturn(mockHotRunner);
 
         final AttachCommand command = AttachCommand(
           hotRunnerFactory: mockHotRunnerFactory,
@@ -121,7 +136,7 @@ void main() {
           projectRoot,
           '--output-dill',
           outputDill,
-          '-v',
+          '-v', // enables verbose logging
         ]);
 
         // Validate the attach call built a mock runner with the right
@@ -191,30 +206,36 @@ void main() {
       final MockDeviceLogReader mockLogReader = MockDeviceLogReader();
       final MockPortForwarder portForwarder = MockPortForwarder();
       final MockAndroidDevice device = MockAndroidDevice();
+      final MockHotRunner mockHotRunner = MockHotRunner();
       final MockHotRunnerFactory mockHotRunnerFactory = MockHotRunnerFactory();
-      when(device.portForwarder).thenReturn(portForwarder);
+      when(device.portForwarder)
+        .thenReturn(portForwarder);
       when(portForwarder.forward(devicePort, hostPort: anyNamed('hostPort')))
-          .thenAnswer((_) async => hostPort);
-      when(portForwarder.forwardedPorts).thenReturn(
-          <ForwardedPort>[ForwardedPort(hostPort, devicePort)]);
-      when(portForwarder.unforward(any)).thenAnswer((_) async => null);
-      when(mockHotRunnerFactory.build(any,
-          target: anyNamed('target'),
-          debuggingOptions: anyNamed('debuggingOptions'),
-          packagesFilePath: anyNamed('packagesFilePath'),
-          usesTerminalUI: anyNamed('usesTerminalUI'),
-          ipv6: false)).thenReturn(
-          MockHotRunner());
+        .thenAnswer((_) async => hostPort);
+      when(portForwarder.forwardedPorts)
+        .thenReturn(<ForwardedPort>[ForwardedPort(hostPort, devicePort)]);
+      when(portForwarder.unforward(any))
+        .thenAnswer((_) async => null);
+      when(mockHotRunner.attach())
+        .thenAnswer((_) async => 0);
+      when(mockHotRunnerFactory.build(
+        any,
+        target: anyNamed('target'),
+        debuggingOptions: anyNamed('debuggingOptions'),
+        packagesFilePath: anyNamed('packagesFilePath'),
+        usesTerminalUI: anyNamed('usesTerminalUI'),
+        ipv6: false,
+      )).thenReturn(mockHotRunner);
 
       testDeviceManager.addDevice(device);
-      when(device.getLogReader()).thenAnswer((_) {
-        // Now that the reader is used, start writing messages to it.
-        Timer.run(() {
-          mockLogReader.addLine('Foo');
-          mockLogReader.addLine(
-              'Observatory listening on http://127.0.0.1:$devicePort');
-        });
-
+      when(device.getLogReader())
+        .thenAnswer((_) {
+          // Now that the reader is used, start writing messages to it.
+          Timer.run(() {
+            mockLogReader.addLine('Foo');
+            mockLogReader.addLine(
+                'Observatory listening on http://127.0.0.1:$devicePort');
+          });
         return mockLogReader;
       });
       final File foo = fs.file('lib/foo.dart')
@@ -223,20 +244,20 @@ void main() {
       // Delete the main.dart file to be sure that attach works without it.
       fs.file('lib/main.dart').deleteSync();
 
-      final AttachCommand command = AttachCommand(
-          hotRunnerFactory: mockHotRunnerFactory);
-      await createTestCommandRunner(command).run(
-          <String>['attach', '-t', foo.path, '-v']);
-
-      verify(mockHotRunnerFactory.build(any,
-          target: foo.path,
-          debuggingOptions: anyNamed('debuggingOptions'),
-          packagesFilePath: anyNamed('packagesFilePath'),
-          usesTerminalUI: anyNamed('usesTerminalUI'),
-          ipv6: false)).called(1);
+      final AttachCommand command = AttachCommand(hotRunnerFactory: mockHotRunnerFactory);
+      await createTestCommandRunner(command).run(<String>['attach', '-t', foo.path, '-v']);
+
+      verify(mockHotRunnerFactory.build(
+        any,
+        target: foo.path,
+        debuggingOptions: anyNamed('debuggingOptions'),
+        packagesFilePath: anyNamed('packagesFilePath'),
+        usesTerminalUI: anyNamed('usesTerminalUI'),
+        ipv6: false,
+      )).called(1);
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-    },);
+    });
 
     group('forwarding to given port', () {
       const int devicePort = 499;
@@ -248,74 +269,121 @@ void main() {
         portForwarder = MockPortForwarder();
         device = MockAndroidDevice();
 
-        when(device.portForwarder).thenReturn(portForwarder);
-        when(portForwarder.forward(devicePort)).thenAnswer((_) async => hostPort);
-        when(portForwarder.forwardedPorts).thenReturn(
-            <ForwardedPort>[ForwardedPort(hostPort, devicePort)]);
-        when(portForwarder.unforward(any)).thenAnswer((_) async => null);
+        when(device.portForwarder)
+          .thenReturn(portForwarder);
+        when(portForwarder.forward(devicePort))
+          .thenAnswer((_) async => hostPort);
+        when(portForwarder.forwardedPorts)
+          .thenReturn(<ForwardedPort>[ForwardedPort(hostPort, devicePort)]);
+        when(portForwarder.unforward(any))
+          .thenAnswer((_) async => null);
       });
 
       testUsingContext('succeeds in ipv4 mode', () async {
         testDeviceManager.addDevice(device);
-        final AttachCommand command = AttachCommand();
-
-        await createTestCommandRunner(command).run(
-            <String>['attach', '--debug-port', '$devicePort']);
 
+        final Completer<void> completer = Completer<void>();
+        final StreamSubscription<String> loggerSubscription = logger.stream.listen((String message) {
+          if (message == '[verbose] Connecting to service protocol: http://127.0.0.1:42/') {
+            // Wait until resident_runner.dart tries to connect.
+            // There's nothing to connect _to_, so that's as far as we care to go.
+            completer.complete();
+          }
+        });
+        final Future<void> task = createTestCommandRunner(AttachCommand())
+          .run(<String>['attach', '--debug-port', '$devicePort']);
+        await completer.future;
         verify(portForwarder.forward(devicePort)).called(1);
+
+        await expectLoggerInterruptEndsTask(task, logger);
+        await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
+        Logger: () => logger,
       });
 
       testUsingContext('succeeds in ipv6 mode', () async {
         testDeviceManager.addDevice(device);
-        final AttachCommand command = AttachCommand();
-
-        await createTestCommandRunner(command).run(
-            <String>['attach', '--debug-port', '$devicePort', '--ipv6']);
 
+        final Completer<void> completer = Completer<void>();
+        final StreamSubscription<String> loggerSubscription = logger.stream.listen((String message) {
+          if (message == '[verbose] Connecting to service protocol: http://[::1]:42/') {
+            // Wait until resident_runner.dart tries to connect.
+            // There's nothing to connect _to_, so that's as far as we care to go.
+            completer.complete();
+          }
+        });
+        final Future<void> task = createTestCommandRunner(AttachCommand())
+          .run(<String>['attach', '--debug-port', '$devicePort', '--ipv6']);
+        await completer.future;
         verify(portForwarder.forward(devicePort)).called(1);
+
+        await expectLoggerInterruptEndsTask(task, logger);
+        await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
+        Logger: () => logger,
       });
 
       testUsingContext('skips in ipv4 mode with a provided observatory port', () async {
         testDeviceManager.addDevice(device);
-        final AttachCommand command = AttachCommand();
 
-        await createTestCommandRunner(command).run(
-            <String>[
-              'attach',
-              '--debug-port',
-              '$devicePort',
-              '--observatory-port',
-              '$hostPort',
-            ],
+        final Completer<void> completer = Completer<void>();
+        final StreamSubscription<String> loggerSubscription = logger.stream.listen((String message) {
+          if (message == '[verbose] Connecting to service protocol: http://127.0.0.1:42/') {
+            // Wait until resident_runner.dart tries to connect.
+            // There's nothing to connect _to_, so that's as far as we care to go.
+            completer.complete();
+          }
+        });
+        final Future<void> task = createTestCommandRunner(AttachCommand()).run(
+          <String>[
+            'attach',
+            '--debug-port',
+            '$devicePort',
+            '--observatory-port',
+            '$hostPort',
+          ],
         );
-
+        await completer.future;
         verifyNever(portForwarder.forward(devicePort));
+
+        await expectLoggerInterruptEndsTask(task, logger);
+        await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
+        Logger: () => logger,
       });
 
       testUsingContext('skips in ipv6 mode with a provided observatory port', () async {
         testDeviceManager.addDevice(device);
-        final AttachCommand command = AttachCommand();
 
-        await createTestCommandRunner(command).run(
-            <String>[
-              'attach',
-              '--debug-port',
-              '$devicePort',
-              '--observatory-port',
-              '$hostPort',
-              '--ipv6',
-            ],
+        final Completer<void> completer = Completer<void>();
+        final StreamSubscription<String> loggerSubscription = logger.stream.listen((String message) {
+          if (message == '[verbose] Connecting to service protocol: http://[::1]:42/') {
+            // Wait until resident_runner.dart tries to connect.
+            // There's nothing to connect _to_, so that's as far as we care to go.
+            completer.complete();
+          }
+        });
+        final Future<void> task = createTestCommandRunner(AttachCommand()).run(
+          <String>[
+            'attach',
+            '--debug-port',
+            '$devicePort',
+            '--observatory-port',
+            '$hostPort',
+            '--ipv6',
+          ],
         );
-
+        await completer.future;
         verifyNever(portForwarder.forward(devicePort));
+
+        await expectLoggerInterruptEndsTask(task, logger);
+        await loggerSubscription.cancel();
       }, overrides: <Type, Generator>{
         FileSystem: () => testFileSystem,
+        Logger: () => logger,
       });
     });
 
@@ -328,7 +396,7 @@ void main() {
       expect(testLogger.statusText, contains('No connected devices'));
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-    },);
+    });
 
     testUsingContext('exits when multiple devices connected', () async {
       Device aDeviceWithId(String id) {
@@ -352,7 +420,7 @@ void main() {
       expect(testLogger.statusText, contains('yy2'));
     }, overrides: <Type, Generator>{
       FileSystem: () => testFileSystem,
-    },);
+    });
   });
 }
 
@@ -361,3 +429,83 @@ class MockPortForwarder extends Mock implements DevicePortForwarder {}
 class MockHotRunner extends Mock implements HotRunner {}
 
 class MockHotRunnerFactory extends Mock implements HotRunnerFactory {}
+
+class StreamLogger extends Logger {
+  @override
+  bool get isVerbose => true;
+
+  @override
+  void printError(
+    String message, {
+    StackTrace stackTrace,
+    bool emphasis,
+    TerminalColor color,
+    int indent,
+    int hangingIndent,
+    bool wrap,
+  }) {
+    _log('[stderr] $message');
+  }
+
+  @override
+  void printStatus(
+    String message, {
+    bool emphasis,
+    TerminalColor color,
+    bool newline,
+    int indent,
+    int hangingIndent,
+    bool wrap,
+  }) {
+    _log('[stdout] $message');
+  }
+
+  @override
+  void printTrace(String message) {
+    _log('[verbose] $message');
+  }
+
+  @override
+  Status startProgress(
+    String message, {
+    @required Duration timeout,
+    String progressId,
+    bool multilineOutput = false,
+    int progressIndicatorPadding = kDefaultStatusPadding,
+  }) {
+    _log('[progress] $message');
+    return SilentStatus(timeout: timeout)..start();
+  }
+
+  bool _interrupt = false;
+
+  void interrupt() {
+    _interrupt = true;
+  }
+
+  final StreamController<String> _controller = StreamController<String>.broadcast();
+
+  void _log(String message) {
+    _controller.add(message);
+    if (_interrupt) {
+      _interrupt = false;
+      throw const LoggerInterrupted();
+    }
+  }
+
+  Stream<String> get stream => _controller.stream;
+}
+
+class LoggerInterrupted implements Exception {
+  const LoggerInterrupted();
+}
+
+Future<void> expectLoggerInterruptEndsTask(Future<void> task, StreamLogger logger) async {
+  logger.interrupt(); // an exception during the task should cause it to fail...
+  try {
+    await task;
+    expect(false, isTrue); // (shouldn't reach here)
+  } on ToolExit catch (error) {
+    expect(error.exitCode, 2); // ...with exit code 2.
+  }
+}

packages/flutter_tools/test/integration/daemon_mode_test.dart

@@ -90,5 +90,5 @@ void main() {
       expect(result, isList);
       expect(result, isNotEmpty);
     });
-  }, timeout: const Timeout.factor(2));
+  }, timeout: const Timeout.factor(10)); // This test uses the `flutter` tool, which could be blocked behind the startup lock for a long time.
 }

packages/flutter_tools/test/integration/debugger_stepping_test.dart

@@ -28,13 +28,15 @@ void main() {
     });
 
     test('can step over statements', () async {
-      await _flutter.run(withDebugger: true);
+      await _flutter.run(withDebugger: true, startPaused: true);
+      await _flutter.addBreakpoint(_project.breakpointUri, _project.breakpointLine);
+      await _flutter.resume();
+      await _flutter.waitForPause(); // Now we should be on the breakpoint.
 
-      // Stop at the initial breakpoint that the expected steps are based on.
-      await _flutter.breakAt(_project.breakpointUri, _project.breakpointLine, restart: true);
+      expect((await _flutter.getSourceLocation()).line, equals(_project.breakpointLine));
 
       // Issue 5 steps, ensuring that we end up on the annotated lines each time.
-      for (int i = 1; i <= _project.numberOfSteps; i++) {
+      for (int i = 1; i <= _project.numberOfSteps; i += 1) {
         await _flutter.stepOverOrOverAsyncSuspension();
         final SourcePosition location = await _flutter.getSourceLocation();
         final int actualLine = location.line;
@@ -47,5 +49,5 @@ void main() {
           reason: 'After $i steps, debugger should stop at $expectedLine but stopped at $actualLine');
       }
     });
-  }, timeout: const Timeout.factor(3));
+  }, timeout: const Timeout.factor(10)); // The DevFS sync takes a really long time, so these tests can be slow.
 }

packages/flutter_tools/test/integration/expression_evaluation_test.dart

@@ -32,16 +32,18 @@ void main() {
       tryToDelete(tempDir);
     });
 
-    Future<Isolate> breakInBuildMethod(FlutterTestDriver flutter) async {
-      return _flutter.breakAt(
-          _project.buildMethodBreakpointUri,
-          _project.buildMethodBreakpointLine);
+    Future<void> breakInBuildMethod(FlutterTestDriver flutter) async {
+      await _flutter.breakAt(
+        _project.buildMethodBreakpointUri,
+        _project.buildMethodBreakpointLine,
+      );
     }
 
-    Future<Isolate> breakInTopLevelFunction(FlutterTestDriver flutter) async {
-      return _flutter.breakAt(
-          _project.topLevelFunctionBreakpointUri,
-          _project.topLevelFunctionBreakpointLine);
+    Future<void> breakInTopLevelFunction(FlutterTestDriver flutter) async {
+      await _flutter.breakAt(
+        _project.topLevelFunctionBreakpointUri,
+        _project.topLevelFunctionBreakpointLine,
+      );
     }
 
     test('can evaluate trivial expressions in top level function', () async {
@@ -79,7 +81,7 @@ void main() {
       await breakInBuildMethod(_flutter);
       await evaluateComplexReturningExpressions(_flutter);
     });
-  }, timeout: const Timeout.factor(6));
+  }, timeout: const Timeout.factor(10)); // The DevFS sync takes a really long time, so these tests can be slow.
 
   group('flutter test expression evaluation', () {
     Directory tempDir;
@@ -124,7 +126,7 @@ void main() {
       await evaluateComplexReturningExpressions(_flutter);
     });
     // Skipped due to https://github.com/flutter/flutter/issues/26518
-  }, timeout: const Timeout.factor(6));
+  }, timeout: const Timeout.factor(10), skip: true); // The DevFS sync takes a really long time, so these tests can be slow.
 }
 
 Future<void> evaluateTrivialExpressions(FlutterTestDriver flutter) async {

packages/flutter_tools/test/integration/flutter_attach_test.dart

@@ -18,8 +18,8 @@ void main() {
   setUp(() async {
     tempDir = createResolvedTempDirectorySync('attach_test.');
     await _project.setUpIn(tempDir);
-    _flutterRun = FlutterRunTestDriver(tempDir, logPrefix: 'RUN');
-    _flutterAttach = FlutterRunTestDriver(tempDir, logPrefix: 'ATTACH');
+    _flutterRun = FlutterRunTestDriver(tempDir,    logPrefix: '   RUN  ');
+    _flutterAttach = FlutterRunTestDriver(tempDir, logPrefix: 'ATTACH  ');
   });
 
   tearDown(() async {
@@ -58,5 +58,5 @@ void main() {
       await _flutterAttach.attach(_flutterRun.vmServicePort);
       await _flutterAttach.hotReload();
     });
-  }, timeout: const Timeout.factor(6));
+  }, timeout: const Timeout.factor(10)); // The DevFS sync takes a really long time, so these tests can be slow.
 }

packages/flutter_tools/test/integration/flutter_run_test.dart

@@ -55,5 +55,5 @@ void main() {
       await _flutter.run(pidFile: pidFile);
       expect(pidFile.existsSync(), isTrue);
     });
-  }, timeout: const Timeout.factor(6));
+  }, timeout: const Timeout.factor(10)); // The DevFS sync takes a really long time, so these tests can be slow.
 }

packages/flutter_tools/test/integration/hot_reload_test.dart

@@ -14,7 +14,7 @@ import 'test_driver.dart';
 import 'test_utils.dart';
 
 void main() {
-  group('hot', () {
+  group('hot reload tests', () {
     Directory tempDir;
     final HotReloadProject _project = HotReloadProject();
     FlutterRunTestDriver _flutter;
@@ -26,39 +26,127 @@ void main() {
     });
 
     tearDown(() async {
-      await _flutter.stop();
+      await _flutter?.stop();
       tryToDelete(tempDir);
     });
 
-    test('reload works without error', () async {
+    test('hot reload works without error', () async {
       await _flutter.run();
       await _flutter.hotReload();
     });
 
-    test('newly added code executes during reload', () async {
+    test('newly added code executes during hot reload', () async {
       await _flutter.run();
       _project.uncommentHotReloadPrint();
       final StringBuffer stdout = StringBuffer();
-      final StreamSubscription<String> sub = _flutter.stdout.listen(stdout.writeln);
+      final StreamSubscription<String> subscription = _flutter.stdout.listen(stdout.writeln);
       try {
             await _flutter.hotReload();
             expect(stdout.toString(), contains('(((((RELOAD WORKED)))))'));
       } finally {
-        await sub.cancel();
+        await subscription.cancel();
       }
     });
 
-    test('restart works without error', () async {
+    test('hot restart works without error', () async {
       await _flutter.run();
       await _flutter.hotRestart();
     });
 
-    test('reload hits breakpoints after reload', () async {
+    test('breakpoints are hit after hot reload', () async {
+      Isolate isolate;
+      await _flutter.run(withDebugger: true, startPaused: true);
+      final Completer<void> sawTick1 = Completer<void>();
+      final Completer<void> sawTick3 = Completer<void>();
+      final Completer<void> sawDebuggerPausedMessage = Completer<void>();
+      final StreamSubscription<String> subscription = _flutter.stdout.listen(
+        (String line) {
+          if (line.contains('((((TICK 1))))')) {
+            expect(sawTick1.isCompleted, isFalse);
+            sawTick1.complete();
+          }
+          if (line.contains('((((TICK 3))))')) {
+            expect(sawTick3.isCompleted, isFalse);
+            sawTick3.complete();
+          }
+          if (line.contains('The application is paused in the debugger on a breakpoint.')) {
+            expect(sawDebuggerPausedMessage.isCompleted, isFalse);
+            sawDebuggerPausedMessage.complete();
+          }
+        },
+      );
+      await _flutter.resume(); // we start paused so we can set up our TICK 1 listener before the app starts
+      sawTick1.future.timeout( // ignore: unawaited_futures
+        const Duration(seconds: 5),
+        onTimeout: () { print('The test app is taking longer than expected to print its synchronization line...'); },
+      );
+      await sawTick1.future; // after this, app is in steady state
+      await _flutter.addBreakpoint(
+        _project.scheduledBreakpointUri,
+        _project.scheduledBreakpointLine,
+      );
+      await _flutter.hotReload(); // reload triggers code which eventually hits the breakpoint
+      isolate = await _flutter.waitForPause();
+      expect(isolate.pauseEvent.kind, equals(EventKind.kPauseBreakpoint));
+      await _flutter.resume();
+      await _flutter.addBreakpoint(
+        _project.buildBreakpointUri,
+        _project.buildBreakpointLine,
+      );
+      bool reloaded = false;
+      final Future<void> reloadFuture = _flutter.hotReload().then((void value) { reloaded = true; });
+      await sawTick3.future; // this should happen before it pauses
+      isolate = await _flutter.waitForPause();
+      expect(isolate.pauseEvent.kind, equals(EventKind.kPauseBreakpoint));
+      await sawDebuggerPausedMessage.future;
+      expect(reloaded, isFalse);
+      await _flutter.resume();
+      await reloadFuture;
+      expect(reloaded, isTrue);
+      reloaded = false;
+      await subscription.cancel();
+    });
+
+    test('hot reload doesn\'t reassemble if paused', () async {
       await _flutter.run(withDebugger: true);
-      final Isolate isolate = await _flutter.breakAt(
-          _project.breakpointUri,
-          _project.breakpointLine);
+      final Completer<void> sawTick2 = Completer<void>();
+      final Completer<void> sawTick3 = Completer<void>();
+      final Completer<void> sawDebuggerPausedMessage1 = Completer<void>();
+      final Completer<void> sawDebuggerPausedMessage2 = Completer<void>();
+      final StreamSubscription<String> subscription = _flutter.stdout.listen(
+        (String line) {
+          if (line.contains('((((TICK 2))))')) {
+            expect(sawTick2.isCompleted, isFalse);
+            sawTick2.complete();
+          }
+          if (line.contains('The application is paused in the debugger on a breakpoint.')) {
+            expect(sawDebuggerPausedMessage1.isCompleted, isFalse);
+            sawDebuggerPausedMessage1.complete();
+          }
+          if (line.contains('The application is paused in the debugger on a breakpoint; interface might not update.')) {
+            expect(sawDebuggerPausedMessage2.isCompleted, isFalse);
+            sawDebuggerPausedMessage2.complete();
+          }
+        },
+      );
+      await _flutter.addBreakpoint(
+        _project.buildBreakpointUri,
+        _project.buildBreakpointLine,
+      );
+      bool reloaded = false;
+      final Future<void> reloadFuture = _flutter.hotReload().then((void value) { reloaded = true; });
+      await sawTick2.future; // this should happen before it pauses
+      final Isolate isolate = await _flutter.waitForPause();
       expect(isolate.pauseEvent.kind, equals(EventKind.kPauseBreakpoint));
+      expect(reloaded, isFalse);
+      await sawDebuggerPausedMessage1.future; // this is the one where it say "uh, you broke into the debugger while reloading"
+      await reloadFuture; // this is the one where it times out because you're in the debugger
+      expect(reloaded, isTrue);
+      await _flutter.hotReload(); // now we're already paused
+      expect(sawTick3.isCompleted, isFalse);
+      await sawDebuggerPausedMessage2.future; // so we just get told that nothing is going to happen
+      await _flutter.resume();
+      await subscription.cancel();
     });
-  }, timeout: const Timeout.factor(6));
+  }, timeout: const Timeout.factor(10)); // The DevFS sync takes a really long time, so these tests can be slow.
 }

packages/flutter_tools/test/integration/lifetime_test.dart

@@ -45,5 +45,5 @@ void main() {
       await Future<void>.delayed(requiredLifespan);
       expect(_flutter.hasExited, equals(false));
     });
-  }, timeout: const Timeout.factor(6));
+  }, timeout: const Timeout.factor(10)); // The DevFS sync takes a really long time, so these tests can be slow.
 }

packages/flutter_tools/test/integration/test_data/basic_project.dart

@@ -19,15 +19,22 @@ class BasicProject extends Project {
 
   @override
   final String main = r'''
+  import 'dart:async';
+
   import 'package:flutter/material.dart';
 
-  void main() => runApp(new MyApp());
+  Future<void> main() async {
+    while (true) {
+      runApp(new MyApp());
+      await Future.delayed(const Duration(milliseconds: 50));
+    }
+  }
 
   class MyApp extends StatelessWidget {
     @override
     Widget build(BuildContext context) {
       topLevelFunction();
-      return new MaterialApp( // BREAKPOINT
+      return new MaterialApp( // BUILD BREAKPOINT
         title: 'Flutter Demo',
         home: new Container(),
       );
@@ -39,9 +46,9 @@ class BasicProject extends Project {
   }
   ''';
 
-  Uri get buildMethodBreakpointUri => breakpointUri;
-  int get buildMethodBreakpointLine => breakpointLine;
+  Uri get buildMethodBreakpointUri => mainDart;
+  int get buildMethodBreakpointLine => lineContaining(main, '// BUILD BREAKPOINT');
 
-  Uri get topLevelFunctionBreakpointUri => breakpointUri;
+  Uri get topLevelFunctionBreakpointUri => mainDart;
   int get topLevelFunctionBreakpointLine => lineContaining(main, '// TOP LEVEL BREAKPOINT');
 }

packages/flutter_tools/test/integration/test_data/hot_reload_project.dart

@@ -22,33 +22,63 @@ class HotReloadProject extends Project {
   @override
   final String main = r'''
   import 'package:flutter/material.dart';
+  import 'package:flutter/scheduler.dart';
 
   void main() => runApp(new MyApp());
 
+  int count = 1;
+
   class MyApp extends StatelessWidget {
     @override
     Widget build(BuildContext context) {
-      // Do not remove this line, it's uncommented by a test to verify that hot
-      // reloading worked.
+      // This method gets called each time we hot reload, during reassemble.
+
+      // Do not remove the next line, it's uncommented by a test to verify that
+      // hot reloading worked:
       // printHotReloadWorked();
 
-      return new MaterialApp( // BREAKPOINT
+      print('((((TICK $count))))');
+      // tick 1 = startup warmup frame
+      // tick 2 = hot reload warmup reassemble frame
+      // after that there's a post-hot-reload frame scheduled by the tool that
+      // doesn't trigger this to rebuild, but does trigger the first callback
+      // below, then that callback schedules another frame on which we do the
+      // breakpoint.
+      // tick 3 = second hot reload warmup reassemble frame (pre breakpoint)
+      if (count == 2) {
+        SchedulerBinding.instance.scheduleFrameCallback((Duration timestamp) {
+          SchedulerBinding.instance.scheduleFrameCallback((Duration timestamp) {
+            print('breakpoint line'); // SCHEDULED BREAKPOINT
+          });
+        });
+      }
+      count += 1;
+
+      return MaterialApp( // BUILD BREAKPOINT
         title: 'Flutter Demo',
-        home: new Container(),
+        home: Container(),
       );
     }
   }
 
-  printHotReloadWorked() {
+  void printHotReloadWorked() {
     // The call to this function is uncommented by a test to verify that hot
     // reloading worked.
     print('(((((RELOAD WORKED)))))');
   }
   ''';
 
+  Uri get scheduledBreakpointUri => mainDart;
+  int get scheduledBreakpointLine => lineContaining(main, '// SCHEDULED BREAKPOINT');
+
+  Uri get buildBreakpointUri => mainDart;
+  int get buildBreakpointLine => lineContaining(main, '// BUILD BREAKPOINT');
+
   void uncommentHotReloadPrint() {
     final String newMainContents = main.replaceAll(
-        '// printHotReloadWorked();', 'printHotReloadWorked();');
+      '// printHotReloadWorked();',
+      'printHotReloadWorked();'
+    );
     writeFile(fs.path.join(dir.path, 'lib', 'main.dart'), newMainContents);
   }
 }

packages/flutter_tools/test/integration/test_data/project.dart

@@ -15,9 +15,7 @@ abstract class Project {
   String get pubspec;
   String get main;
 
-  // Valid locations for a breakpoint for tests that just need to break somewhere.
-  Uri get breakpointUri => Uri.parse('package:test/main.dart');
-  int get breakpointLine => lineContaining(main, '// BREAKPOINT');
+  Uri get mainDart => Uri.parse('package:test/main.dart');
 
   Future<void> setUpIn(Directory dir) async {
     this.dir = dir;
@@ -32,6 +30,6 @@ abstract class Project {
     final int index = contents.split('\n').indexWhere((String l) => l.contains(search));
     if (index == -1)
       throw Exception("Did not find '$search' inside the file");
-    return index;
+    return index + 1; // first line is line 1, not line 0
   }
 }

packages/flutter_tools/test/integration/test_data/stepping_project.dart

@@ -35,11 +35,11 @@ class SteppingProject extends Project {
 
     Future<void> doAsyncStuff() async {
       print("test"); // BREAKPOINT
-      await new Future.value(true); // STEP 1
-      await new Future.microtask(() => true); // STEP 2 // STEP 3
-      await new Future.delayed(const Duration(milliseconds: 1)); // STEP 4 // STEP 5
-      print("done!"); // STEP 6
-    }
+      await new Future.value(true); // STEP 1 // STEP 2
+      await new Future.microtask(() => true); // STEP 3 // STEP 4
+      await new Future.delayed(const Duration(milliseconds: 1)); // STEP 5 // STEP 6
+      print("done!"); // STEP 7
+    } // STEP 8
 
     @override
     Widget build(BuildContext context) {
@@ -51,7 +51,9 @@ class SteppingProject extends Project {
   }
   ''';
 
+  Uri get breakpointUri => mainDart;
+  int get breakpointLine => lineContaining(main, '// BREAKPOINT');
   int lineForStep(int i) => lineContaining(main, '// STEP $i');
 
-  final int numberOfSteps = 6;
+  final int numberOfSteps = 8;
 }

packages/flutter_tools/test/integration/test_data/tests_project.dart

@@ -47,9 +47,7 @@ class TestsProject extends Project {
 
   String get testFilePath => fs.path.join(dir.path, 'test', 'test.dart');
 
-  @override
   Uri get breakpointUri => Uri.file(testFilePath);
 
-  @override
   int get breakpointLine => lineContaining(testContent, '// BREAKPOINT');
 }

packages/flutter_tools/test/integration/test_driver.dart

@@ -8,26 +8,41 @@ import 'dart:convert';
 import 'package:file/file.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
+import 'package:meta/meta.dart';
 import 'package:process/process.dart';
 import 'package:vm_service_lib/vm_service_lib.dart';
 import 'package:vm_service_lib/vm_service_lib_io.dart';
 
 import '../src/common.dart';
 
-// Set this to true for debugging to get JSON written to stdout.
+// Set this to true for debugging to get verbose logs written to stdout.
+// The logs include the following:
+//   <=stdout= data that the flutter tool running in --verbose mode wrote to stdout.
+//   <=stderr= data that the flutter tool running in --verbose mode wrote to stderr.
+//   =stdin=> data that the test sent to the flutter tool over stdin.
+//   =vm=> data that was sent over the VM service channel to the app running on the test device.
+//   <=vm= data that was sent from the app on the test device over the VM service channel.
+//   Messages regarding what the test is doing.
+// If this is false, then only critical errors and logs when things appear to be
+// taking a long time are printed to the console.
 const bool _printDebugOutputToStdOut = false;
-const Duration defaultTimeout = Duration(seconds: 40);
+
+final DateTime startTime = DateTime.now();
+
+const Duration defaultTimeout = Duration(seconds: 5);
 const Duration appStartTimeout = Duration(seconds: 120);
 const Duration quitTimeout = Duration(seconds: 10);
 
 abstract class FlutterTestDriver {
-  FlutterTestDriver(this._projectFolder, {String logPrefix}):
-    _logPrefix = logPrefix != null ? '$logPrefix: ' : '';
+  FlutterTestDriver(
+    this._projectFolder, {
+    String logPrefix,
+  }) : _logPrefix = logPrefix != null ? '$logPrefix: ' : '';
 
   final Directory _projectFolder;
   final String _logPrefix;
-  Process _proc;
-  int _procPid;
+  Process _process;
+  int _processPid;
   final StreamController<String> _stdout = StreamController<String>.broadcast();
   final StreamController<String> _stderr = StreamController<String>.broadcast();
   final StreamController<String> _allMessages = StreamController<String>.broadcast();
@@ -42,101 +57,108 @@ abstract class FlutterTestDriver {
   int get vmServicePort => _vmServiceWsUri.port;
   bool get hasExited => _hasExited;
 
-  String _debugPrint(String msg) {
-    const int maxLength = 500;
-    final String truncatedMsg =
-        msg.length > maxLength ? msg.substring(0, maxLength) + '...' : msg;
-    _allMessages.add(truncatedMsg);
-    if (_printDebugOutputToStdOut) {
-      print('$_logPrefix$truncatedMsg');
+  String lastTime = '';
+  void _debugPrint(String message, { String topic = '' }) {
+    const int maxLength = 2500;
+    final String truncatedMessage = message.length > maxLength ? message.substring(0, maxLength) + '...' : message;
+    final String line = '${topic.padRight(10)} $truncatedMessage';
+    _allMessages.add(line);
+    final int timeInSeconds = DateTime.now().difference(startTime).inSeconds;
+    String time = timeInSeconds.toString().padLeft(5) + 's ';
+    if (time == lastTime) {
+      time = ' ' * time.length;
+    } else {
+      lastTime = time;
     }
-    return msg;
+    if (_printDebugOutputToStdOut)
+      print('$time$_logPrefix$line');
   }
 
   Future<void> _setupProcess(
-    List<String> args, {
+    List<String> arguments, {
     String script,
     bool withDebugger = false,
-    bool pauseOnExceptions = false,
     File pidFile,
   }) async {
     final String flutterBin = fs.path.join(getFlutterRoot(), 'bin', 'flutter');
-    if (withDebugger) {
-        args.add('--start-paused');
-    }
+    if (withDebugger)
+        arguments.add('--start-paused');
+    if (_printDebugOutputToStdOut)
+        arguments.add('--verbose');
     if (pidFile != null) {
-        args.addAll(<String>['--pid-file', pidFile.path]);
+        arguments.addAll(<String>['--pid-file', pidFile.path]);
     }
     if (script != null) {
-      args.add(script);
+      arguments.add(script);
     }
-    _debugPrint('Spawning flutter $args in ${_projectFolder.path}');
+    _debugPrint('Spawning flutter $arguments in ${_projectFolder.path}');
 
     const ProcessManager _processManager = LocalProcessManager();
-    _proc = await _processManager.start(
-        <String>[flutterBin]
-            .followedBy(args)
-            .toList(),
-        workingDirectory: _projectFolder.path,
-        environment: <String, String>{'FLUTTER_TEST': 'true'});
+    _process = await _processManager.start(
+      <String>[flutterBin]
+        .followedBy(arguments)
+        .toList(),
+      workingDirectory: _projectFolder.path,
+      environment: <String, String>{'FLUTTER_TEST': 'true'},
+    );
 
     // This class doesn't use the result of the future. It's made available
     // via a getter for external uses.
-    _proc.exitCode.then((int code) { // ignore: unawaited_futures
+    _process.exitCode.then((int code) { // ignore: unawaited_futures
       _debugPrint('Process exited ($code)');
       _hasExited = true;
     });
-    transformToLines(_proc.stdout).listen((String line) => _stdout.add(line));
-    transformToLines(_proc.stderr).listen((String line) => _stderr.add(line));
+    transformToLines(_process.stdout).listen((String line) => _stdout.add(line));
+    transformToLines(_process.stderr).listen((String line) => _stderr.add(line));
 
     // Capture stderr to a buffer so we can show it all if any requests fail.
     _stderr.stream.listen(_errorBuffer.writeln);
 
     // This is just debug printing to aid running/debugging tests locally.
-    _stdout.stream.listen(_debugPrint);
-    _stderr.stream.listen(_debugPrint);
+    _stdout.stream.listen((String message) => _debugPrint(message, topic: '<=stdout='));
+    _stderr.stream.listen((String message) => _debugPrint(message, topic: '<=stderr='));
   }
 
   Future<void> connectToVmService({bool pauseOnExceptions = false}) async {
-    _vmService = await vmServiceConnectUri(_vmServiceWsUri.toString());
-      _vmService.onSend.listen((String s) => _debugPrint('==> $s'));
-      _vmService.onReceive.listen((String s) => _debugPrint('<== $s'));
-      await Future.wait(<Future<Success>>[
-        _vmService.streamListen('Isolate'),
-        _vmService.streamListen('Debug'),
-      ]);
-
-      // On hot restarts, the isolate ID we have for the Flutter thread will
-      // exit so we need to invalidate our cached ID.
-      _vmService.onIsolateEvent.listen((Event event) {
-        if (event.kind == EventKind.kIsolateExit && event.isolate.id == _flutterIsolateId) {
-          _flutterIsolateId = null;
-        }
-      });
-
-      // Because we start paused, resume so the app is in a "running" state as
-      // expected by tests. Tests will reload/restart as required if they need
-      // to hit breakpoints, etc.
-      await waitForPause();
-      if (pauseOnExceptions) {
-        await _vmService.setExceptionPauseMode(await _getFlutterIsolateId(), ExceptionPauseMode.kUnhandled);
+    _vmService = await vmServiceConnectUri('$_vmServiceWsUri');
+    _vmService.onSend.listen((String s) => _debugPrint(s, topic: '=vm=>'));
+    _vmService.onReceive.listen((String s) => _debugPrint(s, topic: '<=vm='));
+    _vmService.onIsolateEvent.listen((Event event) {
+      if (event.kind == EventKind.kIsolateExit && event.isolate.id == _flutterIsolateId) {
+        // Hot restarts cause all the isolates to exit, so we need to refresh
+        // our idea of what the Flutter isolate ID is.
+        _flutterIsolateId = null;
       }
+    });
+
+    await Future.wait(<Future<Success>>[
+      _vmService.streamListen('Isolate'),
+      _vmService.streamListen('Debug'),
+    ]);
+
+    await waitForPause();
+    if (pauseOnExceptions) {
+      await _vmService.setExceptionPauseMode(
+        await _getFlutterIsolateId(),
+        ExceptionPauseMode.kUnhandled,
+      );
+    }
   }
 
   Future<int> quit() => _killGracefully();
 
   Future<int> _killGracefully() async {
-    if (_procPid == null)
+    if (_processPid == null)
       return -1;
-    _debugPrint('Sending SIGTERM to $_procPid..');
-    Process.killPid(_procPid);
-    return _proc.exitCode.timeout(quitTimeout, onTimeout: _killForcefully);
+    _debugPrint('Sending SIGTERM to $_processPid..');
+    Process.killPid(_processPid);
+    return _process.exitCode.timeout(quitTimeout, onTimeout: _killForcefully);
   }
 
   Future<int> _killForcefully() {
-    _debugPrint('Sending SIGKILL to $_procPid..');
-    Process.killPid(_procPid, ProcessSignal.SIGKILL);
-    return _proc.exitCode;
+    _debugPrint('Sending SIGKILL to $_processPid..');
+    Process.killPid(_processPid, ProcessSignal.SIGKILL);
+    return _process.exitCode;
   }
 
   String _flutterIsolateId;
@@ -155,75 +177,106 @@ abstract class FlutterTestDriver {
     return isolate;
   }
 
+  /// Add a breakpoint and wait for it to trip the program execution.
+  ///
+  /// Only call this when you are absolutely sure that the program under test
+  /// will hit the breakpoint _in the future_.
+  ///
+  /// In particular, do not call this if the program is currently racing to pass
+  /// the line of code you are breaking on. Pretend that calling this will take
+  /// an hour before setting the breakpoint. Would the code still eventually hit
+  /// the breakpoint and stop?
+  Future<void> breakAt(Uri uri, int line) async {
+    await addBreakpoint(uri, line);
+    await waitForPause();
+  }
+
   Future<void> addBreakpoint(Uri uri, int line) async {
-    _debugPrint('Sending breakpoint for $uri:$line');
+    _debugPrint('Sending breakpoint for: $uri:$line');
     await _vmService.addBreakpointWithScriptUri(
-        await _getFlutterIsolateId(), uri.toString(), line);
+      await _getFlutterIsolateId(),
+      uri.toString(),
+      line,
+    );
   }
 
+  // This method isn't racy. If the isolate is already paused,
+  // it will immediately return.
   Future<Isolate> waitForPause() async {
-    _debugPrint('Waiting for isolate to pause');
-    final String flutterIsolate = await _getFlutterIsolateId();
-
-    Future<Isolate> waitForPause() async {
-      final Completer<Event> pauseEvent = Completer<Event>();
-
-      // Start listening for pause events.
-      final StreamSubscription<Event> pauseSub = _vmService.onDebugEvent
-          .where((Event event) =>
-              event.isolate.id == flutterIsolate &&
-              event.kind.startsWith('Pause'))
-          .listen(pauseEvent.complete);
-
-      // But also check if the isolate was already paused (only after we've set
-      // up the sub) to avoid races. If it was paused, we don't need to wait
-      // for the event.
-      final Isolate isolate = await _vmService.getIsolate(flutterIsolate);
-      if (!isolate.pauseEvent.kind.startsWith('Pause')) {
-        await pauseEvent.future;
-      }
+    return _timeoutWithMessages<Isolate>(
+      () async {
+        final String flutterIsolate = await _getFlutterIsolateId();
+        final Completer<Event> pauseEvent = Completer<Event>();
+
+        // Start listening for pause events.
+        final StreamSubscription<Event> pauseSubscription = _vmService.onDebugEvent
+          .where((Event event) {
+            return event.isolate.id == flutterIsolate
+                && event.kind.startsWith('Pause');
+          })
+          .listen((Event event) {
+            if (!pauseEvent.isCompleted)
+              pauseEvent.complete(event);
+          });
+
+        // But also check if the isolate was already paused (only after we've set
+        // up the subscription) to avoid races. If it was paused, we don't need to wait
+        // for the event.
+        final Isolate isolate = await _vmService.getIsolate(flutterIsolate);
+        if (isolate.pauseEvent.kind.startsWith('Pause')) {
+          _debugPrint('Isolate was already paused (${isolate.pauseEvent.kind}).');
+        } else {
+          _debugPrint('Isolate is not already paused, waiting for event to arrive...');
+          await pauseEvent.future;
+        }
 
-      // Cancel the sub on either of the above.
-      await pauseSub.cancel();
+        // Cancel the subscription on either of the above.
+        await pauseSubscription.cancel();
 
-      return _getFlutterIsolate();
-    }
-
-    return _timeoutWithMessages<Isolate>(waitForPause,
-        message: 'Isolate did not pause');
+        return _getFlutterIsolate();
+      },
+      task: 'Waiting for isolate to pause',
+    );
   }
 
+  Future<Isolate> resume({bool waitForNextPause = false}) => _resume(null, waitForNextPause);
+  Future<Isolate> stepOver({bool waitForNextPause = true}) => _resume(StepOption.kOver, waitForNextPause);
+  Future<Isolate> stepOverAsync({ bool waitForNextPause = true }) => _resume(StepOption.kOverAsyncSuspension, waitForNextPause);
+  Future<Isolate> stepInto({bool waitForNextPause = true}) => _resume(StepOption.kInto, waitForNextPause);
+  Future<Isolate> stepOut({bool waitForNextPause = true}) => _resume(StepOption.kOut, waitForNextPause);
+
   Future<bool> isAtAsyncSuspension() async {
     final Isolate isolate = await _getFlutterIsolate();
     return isolate.pauseEvent.atAsyncSuspension == true;
   }
 
-  Future<Isolate> resume({bool wait = true}) => _resume(wait: wait);
-  Future<Isolate> stepOver({bool wait = true}) => _resume(step: StepOption.kOver, wait: wait);
-  Future<Isolate> stepOverAsync({ bool wait = true }) => _resume(step: StepOption.kOverAsyncSuspension, wait: wait);
-  Future<Isolate> stepOverOrOverAsyncSuspension({ bool wait = true }) async {
-    return (await isAtAsyncSuspension()) ? stepOverAsync(wait: wait) : stepOver(wait: wait);
+  Future<Isolate> stepOverOrOverAsyncSuspension({ bool waitForNextPause = true }) async {
+    if (await isAtAsyncSuspension())
+      return await stepOverAsync(waitForNextPause: waitForNextPause);
+    return await stepOver(waitForNextPause: waitForNextPause);
   }
-  Future<Isolate> stepInto({bool wait = true}) => _resume(step: StepOption.kInto, wait: wait);
-  Future<Isolate> stepOut({bool wait = true}) => _resume(step: StepOption.kOut, wait: wait);
 
-  Future<Isolate> _resume({String step, bool wait = true}) async {
-    _debugPrint('Sending resume ($step)');
-    await _timeoutWithMessages<dynamic>(() async => _vmService.resume(await _getFlutterIsolateId(), step: step),
-        message: 'Isolate did not respond to resume ($step)');
-    return wait ? waitForPause() : null;
+  Future<Isolate> _resume(String step, bool waitForNextPause) async {
+    assert(waitForNextPause != null);
+    await _timeoutWithMessages<dynamic>(
+      () async => _vmService.resume(await _getFlutterIsolateId(), step: step),
+      task: 'Resuming isolate (step=$step)',
+    );
+    return waitForNextPause ? waitForPause() : null;
   }
 
   Future<InstanceRef> evaluateInFrame(String expression) async {
     return _timeoutWithMessages<InstanceRef>(
-        () async => await _vmService.evaluateInFrame(await _getFlutterIsolateId(), 0, expression),
-        message: 'Timed out evaluating expression ($expression)');
+      () async => await _vmService.evaluateInFrame(await _getFlutterIsolateId(), 0, expression),
+      task: 'Evaluating expression ($expression)',
+    );
   }
 
   Future<InstanceRef> evaluate(String targetId, String expression) async {
     return _timeoutWithMessages<InstanceRef>(
-        () async => await _vmService.evaluate(await _getFlutterIsolateId(), targetId, expression),
-        message: 'Timed out evaluating expression ($expression for $targetId)');
+      () async => await _vmService.evaluate(await _getFlutterIsolateId(), targetId, expression),
+      task: 'Evaluating expression ($expression for $targetId)',
+    );
   }
 
   Future<Frame> getTopStackFrame() async {
@@ -260,26 +313,29 @@ abstract class FlutterTestDriver {
   Future<Map<String, dynamic>> _waitFor({
     String event,
     int id,
-    Duration timeout,
+    Duration timeout = defaultTimeout,
     bool ignoreAppStopEvent = false,
   }) async {
+    assert(timeout != null);
+    assert(event != null || id != null);
+    assert(event == null || id == null);
+    final String interestingOccurrence = event != null ? '$event event' : 'response to request $id';
     final Completer<Map<String, dynamic>> response = Completer<Map<String, dynamic>>();
-    StreamSubscription<String> sub;
-    sub = _stdout.stream.listen((String line) async {
+    StreamSubscription<String> subscription;
+    subscription = _stdout.stream.listen((String line) async {
       final dynamic json = parseFlutterResponse(line);
       _lastResponse = line;
-      if (json == null) {
+      if (json == null)
         return;
-      } else if (
-          (event != null && json['event'] == event)
-          || (id != null && json['id'] == id)) {
-        await sub.cancel();
+      if ((event != null && json['event'] == event) ||
+          (id    != null && json['id']    == id)) {
+        await subscription.cancel();
+        _debugPrint('OK ($interestingOccurrence)');
         response.complete(json);
       } else if (!ignoreAppStopEvent && json['event'] == 'app.stop') {
-        await sub.cancel();
+        await subscription.cancel();
         final StringBuffer error = StringBuffer();
-        error.write('Received app.stop event while waiting for ');
-        error.write('${event != null ? '$event event' : 'response to request $id.'}.\n\n');
+        error.write('Received app.stop event while waiting for $interestingOccurrence\n\n');
         if (json['params'] != null && json['params']['error'] != null) {
           error.write('${json['params']['error']}\n\n');
         }
@@ -290,67 +346,107 @@ abstract class FlutterTestDriver {
       }
     });
 
-    return _timeoutWithMessages<Map<String, dynamic>>(() => response.future,
-            timeout: timeout,
-            message: event != null
-                ? 'Did not receive expected $event event.'
-                : 'Did not receive response to request "$id".')
-        .whenComplete(() => sub.cancel());
+    return _timeoutWithMessages(
+      () => response.future,
+      timeout: timeout,
+      task: 'Expecting $interestingOccurrence',
+    ).whenComplete(subscription.cancel);
   }
 
-  Future<T> _timeoutWithMessages<T>(Future<T> Function() f, {Duration timeout, String message}) {
-    // Capture output to a buffer so if we don't get the response we want we can show
-    // the output that did arrive in the timeout error.
-    final StringBuffer messages = StringBuffer();
+  Future<T> _timeoutWithMessages<T>(Future<T> Function() callback, {
+    @required String task,
+    Duration timeout = defaultTimeout,
+  }) {
+    assert(task != null);
+    assert(timeout != null);
+
+    if (_printDebugOutputToStdOut) {
+      _debugPrint('$task...');
+      return callback()..timeout(timeout, onTimeout: () {
+        _debugPrint('$task is taking longer than usual...');
+      });
+    }
+
+    // We're not showing all output to the screen, so let's capture the output
+    // that we would have printed if we were, and output it if we take longer
+    // than the timeout or if we get an error.
+    final StringBuffer messages = StringBuffer('$task\n');
     final DateTime start = DateTime.now();
-    void logMessage(String m) {
+    bool timeoutExpired = false;
+    void logMessage(String logLine) {
       final int ms = DateTime.now().difference(start).inMilliseconds;
-      messages.writeln('[+ ${ms.toString().padLeft(5)}] $m');
+      final String formattedLine = '[+ ${ms.toString().padLeft(5)}] $logLine';
+      messages.writeln(formattedLine);
     }
-    final StreamSubscription<String> sub = _allMessages.stream.listen(logMessage);
+    final StreamSubscription<String> subscription = _allMessages.stream.listen(logMessage);
 
-    return f().timeout(timeout ?? defaultTimeout, onTimeout: () {
-      logMessage('<timed out>');
-      throw '$message';
-    }).catchError((dynamic error) {
-      throw '$error\nReceived:\n${messages.toString()}';
-    }).whenComplete(() => sub.cancel());
+    final Future<T> future = callback();
+
+    future.timeout(timeout ?? defaultTimeout, onTimeout: () {
+      print(messages.toString());
+      timeoutExpired = true;
+      print('$task is taking longer than usual...');
+    });
+
+    return future.catchError((dynamic error) {
+      if (!timeoutExpired) {
+        timeoutExpired = true;
+        print(messages.toString());
+      }
+      throw error;
+    }).whenComplete(() => subscription.cancel());
   }
 }
 
 class FlutterRunTestDriver extends FlutterTestDriver {
-  FlutterRunTestDriver(Directory _projectFolder, {String logPrefix}):
-    super(_projectFolder, logPrefix: logPrefix);
+  FlutterRunTestDriver(
+    Directory projectFolder, {
+    String logPrefix,
+  }) : super(projectFolder, logPrefix: logPrefix);
 
   String _currentRunningAppId;
 
-   Future<void> run({
+  Future<void> run({
     bool withDebugger = false,
+    bool startPaused = false,
     bool pauseOnExceptions = false,
     File pidFile,
   }) async {
-    await _setupProcess(<String>[
+    await _setupProcess(
+      <String>[
         'run',
         '--machine',
         '-d',
         'flutter-tester',
-    ], withDebugger: withDebugger, pauseOnExceptions: pauseOnExceptions, pidFile: pidFile);
+      ],
+      withDebugger: withDebugger,
+      startPaused: startPaused,
+      pauseOnExceptions: pauseOnExceptions,
+      pidFile: pidFile,
+    );
   }
 
   Future<void> attach(
     int port, {
     bool withDebugger = false,
+    bool startPaused = false,
     bool pauseOnExceptions = false,
     File pidFile,
   }) async {
-    await _setupProcess(<String>[
+    await _setupProcess(
+      <String>[
         'attach',
         '--machine',
         '-d',
         'flutter-tester',
         '--debug-port',
         '$port',
-    ], withDebugger: withDebugger, pauseOnExceptions: pauseOnExceptions, pidFile: pidFile);
+      ],
+      withDebugger: withDebugger,
+      startPaused: startPaused,
+      pauseOnExceptions: pauseOnExceptions,
+      pidFile: pidFile,
+    );
   }
 
   @override
@@ -358,35 +454,35 @@ class FlutterRunTestDriver extends FlutterTestDriver {
     List<String> args, {
     String script,
     bool withDebugger = false,
+    bool startPaused = false,
     bool pauseOnExceptions = false,
     File pidFile,
   }) async {
+    assert(!startPaused || withDebugger);
     await super._setupProcess(
       args,
       script: script,
       withDebugger: withDebugger,
-      pauseOnExceptions: pauseOnExceptions,
       pidFile: pidFile,
     );
 
     // Stash the PID so that we can terminate the VM more reliably than using
-    // _proc.kill() (because _proc is a shell, because `flutter` is a shell
-    // script).
+    // _process.kill() (`flutter` is a shell script so _process itself is a
+    // shell, not the flutter tool's Dart process).
     final Map<String, dynamic> connected = await _waitFor(event: 'daemon.connected');
-    _procPid = connected['params']['pid'];
+    _processPid = connected['params']['pid'];
 
     // Set this up now, but we don't wait it yet. We want to make sure we don't
     // miss it while waiting for debugPort below.
-    final Future<Map<String, dynamic>> started = _waitFor(event: 'app.started',
-        timeout: appStartTimeout);
+    final Future<Map<String, dynamic>> started = _waitFor(event: 'app.started', timeout: appStartTimeout);
 
     if (withDebugger) {
-      final Map<String, dynamic> debugPort = await _waitFor(event: 'app.debugPort',
-          timeout: appStartTimeout);
+      final Map<String, dynamic> debugPort = await _waitFor(event: 'app.debugPort', timeout: appStartTimeout);
       final String wsUriString = debugPort['params']['wsUri'];
       _vmServiceWsUri = Uri.parse(wsUriString);
       await connectToVmService(pauseOnExceptions: pauseOnExceptions);
-      await resume(wait: false);
+      if (!startPaused)
+        await resume(waitForNextPause: false);
     }
 
     // Now await the started event; if it had already happened the future will
@@ -401,24 +497,26 @@ class FlutterRunTestDriver extends FlutterTestDriver {
     if (_currentRunningAppId == null)
       throw Exception('App has not started yet');
 
-    final dynamic hotReloadResp = await _sendRequest(
-        'app.restart',
-        <String, dynamic>{'appId': _currentRunningAppId, 'fullRestart': fullRestart, 'pause': pause},
+    _debugPrint('Performing ${ pause ? "paused " : "" }${ fullRestart ? "hot restart" : "hot reload" }...');
+    final dynamic hotReloadResponse = await _sendRequest(
+      'app.restart',
+      <String, dynamic>{'appId': _currentRunningAppId, 'fullRestart': fullRestart, 'pause': pause}
     );
+    _debugPrint('${ fullRestart ? "Hot restart" : "Hot reload" } complete.');
 
-    if (hotReloadResp == null || hotReloadResp['code'] != 0)
+    if (hotReloadResponse == null || hotReloadResponse['code'] != 0)
       _throwErrorResponse('Hot ${fullRestart ? 'restart' : 'reload'} request failed');
   }
 
   Future<int> detach() async {
     if (_vmService != null) {
-      _debugPrint('Closing VM service');
+      _debugPrint('Closing VM service...');
       _vmService.dispose();
     }
     if (_currentRunningAppId != null) {
-      _debugPrint('Detaching from app');
+      _debugPrint('Detaching from app...');
       await Future.any<void>(<Future<void>>[
-        _proc.exitCode,
+        _process.exitCode,
         _sendRequest(
           'app.detach',
           <String, dynamic>{'appId': _currentRunningAppId},
@@ -429,19 +527,19 @@ class FlutterRunTestDriver extends FlutterTestDriver {
       );
       _currentRunningAppId = null;
     }
-    _debugPrint('Waiting for process to end');
-    return _proc.exitCode.timeout(quitTimeout, onTimeout: _killGracefully);
+    _debugPrint('Waiting for process to end...');
+    return _process.exitCode.timeout(quitTimeout, onTimeout: _killGracefully);
   }
 
   Future<int> stop() async {
     if (_vmService != null) {
-      _debugPrint('Closing VM service');
+      _debugPrint('Closing VM service...');
       _vmService.dispose();
     }
     if (_currentRunningAppId != null) {
-      _debugPrint('Stopping app');
+      _debugPrint('Stopping application...');
       await Future.any<void>(<Future<void>>[
-        _proc.exitCode,
+        _process.exitCode,
         _sendRequest(
           'app.stop',
           <String, dynamic>{'appId': _currentRunningAppId},
@@ -452,27 +550,13 @@ class FlutterRunTestDriver extends FlutterTestDriver {
       );
       _currentRunningAppId = null;
     }
-    if (_proc != null) {
-      _debugPrint('Waiting for process to end');
-      return _proc.exitCode.timeout(quitTimeout, onTimeout: _killGracefully);
+    if (_process != null) {
+      _debugPrint('Waiting for process to end...');
+      return _process.exitCode.timeout(quitTimeout, onTimeout: _killGracefully);
     }
     return 0;
   }
 
-  Future<Isolate> breakAt(Uri uri, int line, { bool restart = false }) async {
-    if (restart) {
-      // For a hot restart, we need to send the breakpoints after the restart
-      // so we need to pause during the restart to avoid races.
-      await hotRestart(pause: true);
-      await addBreakpoint(uri, line);
-      return resume();
-    } else {
-      await addBreakpoint(uri, line);
-      await hotReload();
-      return waitForPause();
-    }
-  }
-
   int id = 1;
   Future<dynamic> _sendRequest(String method, dynamic params) async {
     final int requestId = id++;
@@ -482,16 +566,16 @@ class FlutterRunTestDriver extends FlutterTestDriver {
       'params': params
     };
     final String jsonEncoded = json.encode(<Map<String, dynamic>>[request]);
-    _debugPrint(jsonEncoded);
+    _debugPrint(jsonEncoded, topic: '=stdin=>');
 
     // Set up the response future before we send the request to avoid any
-    // races. If the method we're calling is app.stop then we tell waitFor not
+    // races. If the method we're calling is app.stop then we tell _waitFor not
     // to throw if it sees an app.stop event before the response to this request.
     final Future<Map<String, dynamic>> responseFuture = _waitFor(
       id: requestId,
       ignoreAppStopEvent: method == 'app.stop',
     );
-    _proc.stdin.writeln(jsonEncoded);
+    _process.stdin.writeln(jsonEncoded);
     final Map<String, dynamic> response = await responseFuture;
 
     if (response['error'] != null || response['result'] == null)
@@ -500,8 +584,8 @@ class FlutterRunTestDriver extends FlutterTestDriver {
     return response['result'];
   }
 
-  void _throwErrorResponse(String msg) {
-    throw '$msg\n\n$_lastResponse\n\n${_errorBuffer.toString()}'.trim();
+  void _throwErrorResponse(String message) {
+    throw '$message\n\n$_lastResponse\n\n${_errorBuffer.toString()}'.trim();
   }
 }
 
@@ -537,7 +621,6 @@ class FlutterTestTestDriver extends FlutterTestDriver {
       args,
       script: script,
       withDebugger: withDebugger,
-      pauseOnExceptions: pauseOnExceptions,
       pidFile: pidFile,
     );
 
@@ -545,7 +628,7 @@ class FlutterTestTestDriver extends FlutterTestDriver {
     // _proc.kill() (because _proc is a shell, because `flutter` is a shell
     // script).
     final Map<String, dynamic> version = await _waitForJson();
-    _procPid = version['pid'];
+    _processPid = version['pid'];
 
     if (withDebugger) {
       final Map<String, dynamic> startedProcess = await _waitFor(event: 'test.startedProcess', timeout: appStartTimeout);
@@ -556,7 +639,7 @@ class FlutterTestTestDriver extends FlutterTestDriver {
       if (beforeStart != null) {
         await beforeStart();
       }
-      await resume(wait: false);
+      await resume(waitForNextPause: false);
     }
   }
 
@@ -566,7 +649,7 @@ class FlutterTestTestDriver extends FlutterTestDriver {
     return _timeoutWithMessages<Map<String, dynamic>>(
       () => _stdout.stream.map<Map<String, dynamic>>(_parseJsonResponse).first,
       timeout: timeout,
-      message: 'Did not receive any JSON.',
+      task: 'Waiting for JSON',
     );
   }
 
@@ -587,8 +670,8 @@ Stream<String> transformToLines(Stream<List<int>> byteStream) {
 Map<String, dynamic> parseFlutterResponse(String line) {
   if (line.startsWith('[') && line.endsWith(']')) {
     try {
-      final Map<String, dynamic> resp = json.decode(line)[0];
-      return resp;
+      final Map<String, dynamic> response = json.decode(line)[0];
+      return response;
     } catch (e) {
       // Not valid JSON, so likely some other output that was surrounded by [brackets]
       return null;

packages/flutter_tools/test/ios/code_signing_test.dart

@@ -470,7 +470,7 @@ class TestTerminal extends AnsiTerminal {
   String bolden(String message) => '<bold>$message</bold>';
 
   @override
-  Stream<String> get onCharInput {
+  Stream<String> get keystrokes {
     return mockTerminalStdInStream;
   }
 }

packages/flutter_tools/test/vmservice_test.dart

@@ -153,13 +153,32 @@ class MockPeer implements rpc.Peer {
 }
 
 void main() {
-  final MockStdio mockStdio = MockStdio();
+  MockStdio mockStdio;
   group('VMService', () {
+    setUp(() {
+      mockStdio = MockStdio();
+    });
+
     testUsingContext('fails connection eagerly in the connect() method', () async {
-      expect(
-        VMService.connect(Uri.parse('http://host.invalid:9999/')),
-        throwsToolExit(),
-      );
+      FakeAsync().run((FakeAsync time) {
+        bool failed = false;
+        final Future<VMService> future = VMService.connect(Uri.parse('http://host.invalid:9999/'));
+        future.whenComplete(() {
+          failed = true;
+        });
+        time.elapse(const Duration(seconds: 5));
+        expect(failed, isFalse);
+        expect(mockStdio.writtenToStdout.join(''), '');
+        expect(mockStdio.writtenToStderr.join(''), '');
+        time.elapse(const Duration(seconds: 5));
+        expect(failed, isFalse);
+        expect(mockStdio.writtenToStdout.join(''), 'This is taking longer than expected...\n');
+        expect(mockStdio.writtenToStderr.join(''), '');
+      });
+    }, overrides: <Type, Generator>{
+      Logger: () => StdoutLogger(),
+      Stdio: () => mockStdio,
+      WebSocketConnector: () => (String url) async => throw const SocketException('test'),
     });
 
     testUsingContext('refreshViews', () {
@@ -167,7 +186,7 @@ void main() {
         bool done = false;
         final MockPeer mockPeer = MockPeer();
         expect(mockPeer.returnedFromSendRequest, 0);
-        final VMService vmService = VMService(mockPeer, null, null, const Duration(seconds: 1), null, null, null);
+        final VMService vmService = VMService(mockPeer, null, null, null, null, null);
         vmService.getVM().then((void value) { done = true; });
         expect(done, isFalse);
         expect(mockPeer.returnedFromSendRequest, 0);