It's time to #deleteDart1 (#18293)

Eliminates support for Dart 1 in flutter_tools, and drops our Dart 1
benchmarks. All commands now run in Dart 1 mode only.

Eliminates --preview-dart-2 / --no-preview-dart-2 support.

dev/bots/test.dart

@@ -68,12 +68,8 @@ Future<Null> _generateDocs() async {
 }
 
 Future<Null> _verifyInternationalizations() async {
-  final EvalResult genResult = await _evalCommand(
-    dart,
-    <String>[
-      '--preview-dart-2',
-      path.join('dev', 'tools', 'gen_localizations.dart'),
-    ],
+  final EvalResult genResult = await _evalCommand(dart,
+    <String>[ '--preview-dart-2', path.join('dev', 'tools', 'gen_localizations.dart'), ],
     workingDirectory: flutterRoot,
   );
 

dev/devicelab/bin/tasks/gradle_plugin_test.dart

@@ -32,14 +32,6 @@ void main() async {
         return new TaskResult.failure(errorMessage);
       }
 
-      section('gradlew assembleDebug no-preview-dart-2');
-      await project.runGradleTask('assembleDebug', options: <String>['-Ppreview-dart-2=false']);
-      errorMessage = _validateSnapshotDependency(project,
-          '${project.rootPath}/build/app/intermediates/flutter/debug/snapshot_blob.bin');
-      if (errorMessage != null) {
-        return new TaskResult.failure(errorMessage);
-      }
-
       section('gradlew assembleProfile');
       await project.runGradleTask('assembleProfile');
 

dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark_dart1.dart

-// Copyright (c) 2017 The Chromium Authors. All rights reserved.
-// 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_devicelab/tasks/hot_mode_tests.dart';
-import 'package:flutter_devicelab/framework/framework.dart';
-
-Future<Null> main() async {
-  await task(createHotModeTest(isPreviewDart2: false));
-}

dev/devicelab/bin/tasks/hot_mode_dev_cycle_ios__benchmark_dart1.dart

-// Copyright (c) 2018 The Chromium Authors. All rights reserved.
-// 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_devicelab/tasks/hot_mode_tests.dart';
-import 'package:flutter_devicelab/framework/framework.dart';
-import 'package:flutter_devicelab/framework/adb.dart';
-
-Future<Null> main() async {
-  deviceOperatingSystem = DeviceOperatingSystem.ios;
-  await task(createHotModeTest(isPreviewDart2: false));
-}

dev/devicelab/lib/tasks/hot_mode_tests.dart

@@ -16,7 +16,7 @@ import '../framework/utils.dart';
 final Directory _editedFlutterGalleryDir = dir(path.join(Directory.systemTemp.path, 'edited_flutter_gallery'));
 final Directory flutterGalleryDir = dir(path.join(flutterDirectory.path, 'examples/flutter_gallery'));
 
-TaskFunction createHotModeTest({ bool isPreviewDart2 = true }) {
+TaskFunction createHotModeTest() {
   return () async {
     final Device device = await devices.workingDevice;
     await device.unlock();
@@ -25,10 +25,6 @@ TaskFunction createHotModeTest({ bool isPreviewDart2 = true }) {
     final List<String> options = <String>[
       '--hot', '-d', device.deviceId, '--benchmark', '--verbose', '--resident'
     ];
-    if (isPreviewDart2)
-      options.add('--preview-dart-2');
-    else
-      options.add('--no-preview-dart-2');
     setLocalEngineOptionIfNecessary(options);
     int hotReloadCount = 0;
     Map<String, dynamic> twoReloadsData;
@@ -92,8 +88,8 @@ TaskFunction createHotModeTest({ bool isPreviewDart2 = true }) {
         }
         benchmarkFile.deleteSync();
 
-        // start `flutter run` again to make sure it loads from the previous state
-        // (in case of --preview-dart-2 frontend loads up from previously generated kernel files).
+        // start `flutter run` again to make sure it loads from the previous
+        // state; frontend loads up from previously generated kernel files.
         {
           final Process process = await startProcess(
               path.join(flutterDirectory.path, 'bin', 'flutter'),

dev/devicelab/lib/tasks/microbenchmarks.dart

@@ -23,7 +23,7 @@ TaskFunction createMicrobenchmarkTask() {
     final Device device = await devices.workingDevice;
     await device.unlock();
 
-    Future<Map<String, double>> _runMicrobench(String benchmarkPath, {bool previewDart2 = true}) async {
+    Future<Map<String, double>> _runMicrobench(String benchmarkPath) async {
       Future<Map<String, double>> _run() async {
         print('Running $benchmarkPath');
         final Directory appDir = dir(
@@ -38,10 +38,6 @@ TaskFunction createMicrobenchmarkTask() {
             '-d',
             device.deviceId,
           ];
-          if (previewDart2)
-            options.add('--preview-dart-2');
-          else
-            options.add('--no-preview-dart-2');
           setLocalEngineOptionIfNecessary(options);
           options.add(benchmarkPath);
           return await _startFlutter(
@@ -61,26 +57,6 @@ TaskFunction createMicrobenchmarkTask() {
     allResults.addAll(await _runMicrobench('lib/gestures/velocity_tracker_bench.dart'));
     allResults.addAll(await _runMicrobench('lib/stocks/animation_bench.dart'));
 
-    // Run micro-benchmarks once again in --no-preview-dart-2 mode.
-    // Append "_dart1" suffix to the result keys to distinguish them from
-    // the original results.
-
-    void addDart1Results(Map<String, double> benchmarkResults) {
-      benchmarkResults.forEach((String key, double result) {
-        allResults[key + '_dart1'] = result;
-      });
-    }
-
-    addDart1Results(await _runMicrobench(
-        'lib/stocks/layout_bench.dart', previewDart2: false));
-    addDart1Results(await _runMicrobench(
-        'lib/stocks/layout_bench.dart', previewDart2: false));
-    addDart1Results(await _runMicrobench(
-        'lib/stocks/build_bench.dart', previewDart2: false));
-    addDart1Results(await _runMicrobench(
-        'lib/gestures/velocity_tracker_bench.dart', previewDart2: false));
-    addDart1Results(await _runMicrobench(
-        'lib/stocks/animation_bench.dart', previewDart2: false));
     return new TaskResult.success(allResults, benchmarkScoreKeys: allResults.keys.toList());
   };
 }

dev/devicelab/lib/tasks/perf_tests.dart

@@ -205,23 +205,13 @@ class CompileTest {
       final Map<String, dynamic> metrics = <String, dynamic>{}
         ..addAll(await _compileAot())
         ..addAll(await _compileApp())
-        ..addAll(await _compileDebug())
-        ..addAll(_suffix(await _compileAot(previewDart2: false), '__dart1'))
-        ..addAll(_suffix(await _compileApp(previewDart2: false), '__dart1'))
-        ..addAll(_suffix(await _compileDebug(previewDart2: false), '__dart1'));
+        ..addAll(await _compileDebug());
 
       return new TaskResult.success(metrics, benchmarkScoreKeys: metrics.keys.toList());
     });
   }
 
-  static Map<String, dynamic> _suffix(Map<String, dynamic> map, String suffix) {
-    return new Map<String, dynamic>.fromIterables(
-      map.keys.map<String>((String key) => '$key$suffix'),
-      map.values,
-    );
-  }
-
-  static Future<Map<String, dynamic>> _compileAot({ bool previewDart2 = true }) async {
+  static Future<Map<String, dynamic>> _compileAot() async {
     // Generate blobs instead of assembly.
     await flutter('clean');
     final Stopwatch watch = new Stopwatch()..start();
@@ -240,10 +230,6 @@ class CompileTest {
         options.add('android-arm');
         break;
     }
-    if (previewDart2)
-      options.add('--preview-dart-2');
-    else
-      options.add('--no-preview-dart-2');
     setLocalEngineOptionIfNecessary(options);
     final String compileLog = await evalFlutter('build', options: options);
     watch.stop();
@@ -258,15 +244,11 @@ class CompileTest {
     return metrics;
   }
 
-  static Future<Map<String, dynamic>> _compileApp({ bool previewDart2 = true }) async {
+  static Future<Map<String, dynamic>> _compileApp() async {
     await flutter('clean');
     final Stopwatch watch = new Stopwatch();
     int releaseSizeInBytes;
     final List<String> options = <String>['--release'];
-    if (previewDart2)
-      options.add('--preview-dart-2');
-    else
-      options.add('--no-preview-dart-2');
     setLocalEngineOptionIfNecessary(options);
     switch (deviceOperatingSystem) {
       case DeviceOperatingSystem.ios:
@@ -299,14 +281,10 @@ class CompileTest {
     };
   }
 
-  static Future<Map<String, dynamic>> _compileDebug({ bool previewDart2 = true }) async {
+  static Future<Map<String, dynamic>> _compileDebug() async {
     await flutter('clean');
     final Stopwatch watch = new Stopwatch();
     final List<String> options = <String>['--debug'];
-    if (previewDart2)
-      options.add('--preview-dart-2');
-    else
-      options.add('--no-preview-dart-2');
     setLocalEngineOptionIfNecessary(options);
     switch (deviceOperatingSystem) {
       case DeviceOperatingSystem.ios:

dev/devicelab/manifest.yaml

@@ -154,21 +154,6 @@ tasks:
     stage: devicelab
     required_agent_capabilities: ["mac/android"]
 
-  hot_mode_dev_cycle__benchmark_dart1:
-    description: >
-      Measures the performance of Dart VM hot patching feature under
-      --no-preview-dart-2 option, that disables Dart 2.0 frontend.
-    stage: devicelab
-    required_agent_capabilities: ["mac/android"]
-
-  hot_mode_dev_cycle_ios__benchmark_dart1:
-    description: >
-      Measures the performance of Dart VM hot patching feature under
-      --no-preview-dart-2 option, that disables Dart 2.0 frontend.
-    stage: devicelab_ios
-    required_agent_capabilities: ["mac/ios"]
-    flaky: true
-
   complex_layout_scroll_perf__memory:
     description: >
       Measures memory usage of the scroll performance test.

packages/flutter_tools/bin/xcode_backend.sh

@@ -102,13 +102,6 @@ BuildApp() {
     local_engine_flag="--local-engine=$LOCAL_ENGINE"
   fi
 
-  local preview_dart_2_flag=""
-  if [[ -n "$PREVIEW_DART_2" ]]; then
-    preview_dart_2_flag="--preview-dart-2"
-  else
-    preview_dart_2_flag="--no-preview-dart-2"
-  fi
-
   local track_widget_creation_flag=""
   if [[ -n "$TRACK_WIDGET_CREATION" ]]; then
     track_widget_creation_flag="--track-widget-creation"
@@ -127,7 +120,6 @@ BuildApp() {
       --${build_mode}                                                       \
       --ios-arch="${archs}"                                                 \
       ${local_engine_flag}                                                  \
-      ${preview_dart_2_flag}                                                \
       ${track_widget_creation_flag}
 
     if [[ $? -ne 0 ]]; then
@@ -167,12 +159,10 @@ BuildApp() {
     ${verbose_flag}                                                         \
     build bundle                                                            \
     --target="${target_path}"                                               \
-    --snapshot="${build_dir}/snapshot_blob.bin"                             \
     --depfile="${build_dir}/snapshot_blob.bin.d"                            \
     --asset-dir="${derived_dir}/flutter_assets"                             \
     ${precompilation_flag}                                                  \
     ${local_engine_flag}                                                    \
-    ${preview_dart_2_flag}                                                  \
     ${track_widget_creation_flag}
 
   if [[ $? -ne 0 ]]; then

packages/flutter_tools/gradle/flutter.gradle

@@ -260,10 +260,6 @@ class FlutterPlugin implements Plugin<Project> {
         if (project.hasProperty('verbose')) {
             verboseValue = project.property('verbose').toBoolean()
         }
-        Boolean previewDart2Value = true
-        if (project.hasProperty('preview-dart-2')) {
-            previewDart2Value = project.property('preview-dart-2').toBoolean()
-        }
         String[] fileSystemRootsValue = null
         if (project.hasProperty('filesystem-roots')) {
             fileSystemRootsValue = project.property('filesystem-roots').split('\\|')
@@ -315,7 +311,6 @@ class FlutterPlugin implements Plugin<Project> {
                 localEngineSrcPath this.localEngineSrcPath
                 targetPath target
                 verbose verboseValue
-                previewDart2 previewDart2Value
                 fileSystemRoots fileSystemRootsValue
                 fileSystemScheme fileSystemSchemeValue
                 trackWidgetCreation trackWidgetCreationValue
@@ -360,8 +355,6 @@ abstract class BaseFlutterTask extends DefaultTask {
     @Optional @Input
     Boolean verbose
     @Optional @Input
-    Boolean previewDart2
-    @Optional @Input
     String[] fileSystemRoots
     @Optional @Input
     String fileSystemScheme
@@ -383,12 +376,10 @@ abstract class BaseFlutterTask extends DefaultTask {
         if (buildMode != 'debug') {
             // For AOT builds, include the gen_snapshot depfile.
             FileCollection depfiles = project.files("${intermediateDir}/snapshot.d")
-            if (previewDart2) {
-                // For Dart 2, also include the kernel compiler depfile, since
-                // kernel compile is the first stage of AOT build in this mode,
-                // and it includes all the Dart sources.
-                depfiles += project.files("${intermediateDir}/kernel_compile.d")
-            }
+            // Include the kernel compiler depfile, since kernel compile is the
+            // first stage of AOT build in this mode, and it includes all the
+            // Dart sources.
+            depfiles += project.files("${intermediateDir}/kernel_compile.d")
             return depfiles
         }
         return project.files("${intermediateDir}/snapshot_blob.bin.d")
@@ -415,11 +406,6 @@ abstract class BaseFlutterTask extends DefaultTask {
                 args "--target", targetPath
                 args "--target-platform", "android-arm"
                 args "--output-dir", "${intermediateDir}"
-                if (previewDart2) {
-                    args "--preview-dart-2"
-                } else {
-                    args "--no-preview-dart-2"
-                }
                 if (trackWidgetCreation) {
                     args "--track-widget-creation"
                 }
@@ -452,11 +438,6 @@ abstract class BaseFlutterTask extends DefaultTask {
             if (verbose) {
                 args "--verbose"
             }
-            if (previewDart2) {
-                args "--preview-dart-2"
-            } else {
-                args "--no-preview-dart-2"
-            }
             if (fileSystemRoots != null) {
                 for (root in fileSystemRoots) {
                     args "--filesystem-root", root
@@ -475,9 +456,6 @@ abstract class BaseFlutterTask extends DefaultTask {
                 args "--precompiled"
             } else {
                 args "--depfile", "${intermediateDir}/snapshot_blob.bin.d"
-                if (!previewDart2) {
-                    args "--snapshot", "${intermediateDir}/snapshot_blob.bin"
-                }
             }
             args "--asset-dir", "${intermediateDir}/flutter_assets"
         }
@@ -533,9 +511,7 @@ class FlutterTask extends BaseFlutterTask {
             // We have a dependencies file. Add a dependency on gen_snapshot as well, since the
             // snapshots have to be rebuilt if it changes.
             sources += readDependencies(project.file("${intermediateDir}/gen_snapshot.d"))
-            if (previewDart2) {
-                sources += readDependencies(project.file("${intermediateDir}/frontend_server.d"))
-            }
+            sources += readDependencies(project.file("${intermediateDir}/frontend_server.d"))
             if (localEngineSrcPath != null) {
                 sources += project.files("$localEngineSrcPath/$localEngine")
             }

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

@@ -327,21 +327,16 @@ Future<Null> _buildGradleProjectV2(String gradle, BuildInfo buildInfo, String ta
   if (target != null) {
     command.add('-Ptarget=$target');
   }
-  if (buildInfo.previewDart2) {
-    command.add('-Ppreview-dart-2=true');
-    if (buildInfo.trackWidgetCreation)
-      command.add('-Ptrack-widget-creation=true');
-    if (buildInfo.extraFrontEndOptions != null)
-      command.add('-Pextra-front-end-options=${buildInfo.extraFrontEndOptions}');
-    if (buildInfo.extraGenSnapshotOptions != null)
-      command.add('-Pextra-gen-snapshot-options=${buildInfo.extraGenSnapshotOptions}');
-    if (buildInfo.fileSystemRoots != null && buildInfo.fileSystemRoots.isNotEmpty)
-      command.add('-Pfilesystem-roots=${buildInfo.fileSystemRoots.join('|')}');
-    if (buildInfo.fileSystemScheme != null)
-      command.add('-Pfilesystem-scheme=${buildInfo.fileSystemScheme}');
-  } else {
-    command.add('-Ppreview-dart-2=false');
-  }
+  if (buildInfo.trackWidgetCreation)
+    command.add('-Ptrack-widget-creation=true');
+  if (buildInfo.extraFrontEndOptions != null)
+    command.add('-Pextra-front-end-options=${buildInfo.extraFrontEndOptions}');
+  if (buildInfo.extraGenSnapshotOptions != null)
+    command.add('-Pextra-gen-snapshot-options=${buildInfo.extraGenSnapshotOptions}');
+  if (buildInfo.fileSystemRoots != null && buildInfo.fileSystemRoots.isNotEmpty)
+    command.add('-Pfilesystem-roots=${buildInfo.fileSystemRoots.join('|')}');
+  if (buildInfo.fileSystemScheme != null)
+    command.add('-Pfilesystem-scheme=${buildInfo.fileSystemScheme}');
   if (buildInfo.buildSharedLibrary && androidSdk.ndk != null) {
     command.add('-Pbuild-shared-library=true');
   }

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

@@ -64,70 +64,6 @@ class GenSnapshot {
   }
 }
 
-/// Dart snapshot builder.
-///
-/// Builds Dart snapshots in one of three modes:
-///   * Script snapshot: architecture-independent snapshot of a Dart script
-///     and core libraries.
-///   * AOT snapshot: architecture-specific ahead-of-time compiled snapshot
-///     suitable for loading with `mmap`.
-///   * Assembly AOT snapshot: architecture-specific ahead-of-time compile to
-///     assembly suitable for compilation as a static or dynamic library.
-class ScriptSnapshotter {
-  /// Builds an architecture-independent snapshot of the specified script.
-  Future<int> build({
-    @required String mainPath,
-    @required String snapshotPath,
-    @required String depfilePath,
-    @required String packagesPath
-  }) async {
-    final SnapshotType snapshotType = new SnapshotType(null, BuildMode.debug);
-    final String vmSnapshotData = artifacts.getArtifactPath(Artifact.vmSnapshotData);
-    final String isolateSnapshotData = artifacts.getArtifactPath(Artifact.isolateSnapshotData);
-    final List<String> args = <String>[
-      '--snapshot_kind=script',
-      '--script_snapshot=$snapshotPath',
-      '--vm_snapshot_data=$vmSnapshotData',
-      '--isolate_snapshot_data=$isolateSnapshotData',
-      '--enable-mirrors=false',
-      mainPath,
-    ];
-
-    final Fingerprinter fingerprinter = new Fingerprinter(
-      fingerprintPath: '$depfilePath.fingerprint',
-      paths: <String>[
-        mainPath,
-        snapshotPath,
-        vmSnapshotData,
-        isolateSnapshotData,
-      ],
-      properties: <String, String>{
-        'buildMode': snapshotType.mode.toString(),
-        'targetPlatform': snapshotType.platform?.toString() ?? '',
-        'entryPoint': mainPath,
-      },
-      depfilePaths: <String>[depfilePath],
-    );
-    if (await fingerprinter.doesFingerprintMatch()) {
-      printTrace('Skipping script snapshot build. Fingerprints match.');
-      return 0;
-    }
-
-    // Build the snapshot.
-    final int exitCode = await genSnapshot.run(
-      snapshotType: snapshotType,
-      packagesPath: packagesPath,
-      depfilePath: depfilePath,
-      additionalArgs: args,
-    );
-
-    if (exitCode != 0)
-      return exitCode;
-    await fingerprinter.writeFingerprint();
-    return exitCode;
-  }
-}
-
 class AOTSnapshotter {
   /// Builds an architecture-specific ahead-of-time compiled snapshot of the specified script.
   Future<int> build({
@@ -136,7 +72,6 @@ class AOTSnapshotter {
     @required String mainPath,
     @required String packagesPath,
     @required String outputPath,
-    @required bool previewDart2,
     @required bool buildSharedLibrary,
     IOSArch iosArch,
     List<String> extraGenSnapshotOptions = const <String>[],
@@ -192,12 +127,10 @@ class AOTSnapshotter {
       '--embedder_entry_points_manifest=$ioEntryPoints',
       '--dependencies=$depfilePath',
     ];
-    if (previewDart2) {
-      genSnapshotArgs.addAll(<String>[
-        '--reify-generic-functions',
-        '--strong',
-      ]);
-    }
+    genSnapshotArgs.addAll(<String>[
+      '--reify-generic-functions',
+      '--strong',
+    ]);
     if (extraGenSnapshotOptions != null && extraGenSnapshotOptions.isNotEmpty) {
       printTrace('Extra gen_snapshot options: $extraGenSnapshotOptions');
       genSnapshotArgs.addAll(extraGenSnapshotOptions);
@@ -252,7 +185,6 @@ class AOTSnapshotter {
         'buildMode': buildMode.toString(),
         'targetPlatform': platform.toString(),
         'entryPoint': mainPath,
-        'dart2': previewDart2.toString(),
         'sharedLib': buildSharedLibrary.toString(),
         'extraGenSnapshotOptions': extraGenSnapshotOptions.join(' '),
       },

packages/flutter_tools/lib/src/build_info.dart

@@ -11,7 +11,6 @@ import 'globals.dart';
 /// Information about a build to be performed or used.
 class BuildInfo {
   const BuildInfo(this.mode, this.flavor, {
-    this.previewDart2 = false,
     this.trackWidgetCreation = false,
     this.extraFrontEndOptions,
     this.extraGenSnapshotOptions,
@@ -33,9 +32,6 @@ class BuildInfo {
   /// Mode-Flavor (e.g. Release-Paid).
   final String flavor;
 
-  /// Whether build should be done using Dart2 Frontend parser.
-  final bool previewDart2;
-
   final List<String> fileSystemRoots;
   final String fileSystemScheme;
 
@@ -93,7 +89,6 @@ class BuildInfo {
 
   BuildInfo withTargetPlatform(TargetPlatform targetPlatform) =>
       new BuildInfo(mode, flavor,
-          previewDart2: previewDart2,
           trackWidgetCreation: trackWidgetCreation,
           extraFrontEndOptions: extraFrontEndOptions,
           extraGenSnapshotOptions: extraGenSnapshotOptions,

packages/flutter_tools/lib/src/bundle.dart

@@ -6,7 +6,6 @@ import 'dart:async';
 
 import 'artifacts.dart';
 import 'asset.dart';
-import 'base/build.dart';
 import 'base/common.dart';
 import 'base/file_system.dart';
 import 'build_info.dart';
@@ -24,7 +23,6 @@ String get defaultApplicationKernelPath => fs.path.join(getBuildDirectory(), 'ap
 const String defaultPrivateKeyPath = 'privatekey.der';
 
 const String _kKernelKey = 'kernel_blob.bin';
-const String _kSnapshotKey = 'snapshot_blob.bin';
 const String _kVMSnapshotData = 'vm_snapshot_data';
 const String _kIsolateSnapshotData = 'isolate_snapshot_data';
 const String _kDylibKey = 'libapp.so';
@@ -33,13 +31,11 @@ const String _kPlatformKernelKey = 'platform.dill';
 Future<void> build({
   String mainPath = defaultMainPath,
   String manifestPath = defaultManifestPath,
-  String snapshotPath,
   String applicationKernelFilePath,
   String depfilePath,
   String privateKeyPath = defaultPrivateKeyPath,
   String assetDirPath,
   String packagesPath,
-  bool previewDart2  = false,
   bool precompiledSnapshot = false,
   bool reportLicensedPackages = false,
   bool trackWidgetCreation = false,
@@ -47,32 +43,13 @@ Future<void> build({
   List<String> fileSystemRoots,
   String fileSystemScheme,
 }) async {
-  snapshotPath ??= defaultSnapshotPath;
   depfilePath ??= defaultDepfilePath;
   assetDirPath ??= getAssetBuildDirectory();
   packagesPath ??= fs.path.absolute(PackageMap.globalPackagesPath);
   applicationKernelFilePath ??= defaultApplicationKernelPath;
-  File snapshotFile;
-
-  if (!precompiledSnapshot && !previewDart2) {
-    ensureDirectoryExists(snapshotPath);
-
-    // In a precompiled snapshot, the instruction buffer contains script
-    // content equivalents
-    final int result = await new ScriptSnapshotter().build(
-      mainPath: mainPath,
-      snapshotPath: snapshotPath,
-      depfilePath: depfilePath,
-      packagesPath: packagesPath,
-    );
-    if (result != 0)
-      throwToolExit('Failed to run the Flutter compiler. Exit code: $result', exitCode: result);
-
-    snapshotFile = fs.file(snapshotPath);
-  }
 
   DevFSContent kernelContent;
-  if (!precompiledSnapshot && previewDart2) {
+  if (!precompiledSnapshot) {
     if ((extraFrontEndOptions != null) && extraFrontEndOptions.isNotEmpty)
       printTrace('Extra front-end options: $extraFrontEndOptions');
     ensureDirectoryExists(applicationKernelFilePath);
@@ -109,7 +86,6 @@ Future<void> build({
   await assemble(
     assetBundle: assets,
     kernelContent: kernelContent,
-    snapshotFile: snapshotFile,
     privateKeyPath: privateKeyPath,
     assetDirPath: assetDirPath,
   );
@@ -143,7 +119,6 @@ Future<AssetBundle> buildAssets({
 Future<void> assemble({
   AssetBundle assetBundle,
   DevFSContent kernelContent,
-  File snapshotFile,
   File dylibFile,
   String privateKeyPath = defaultPrivateKeyPath,
   String assetDirPath,
@@ -152,21 +127,16 @@ Future<void> assemble({
   printTrace('Building bundle');
 
   final Map<String, DevFSContent> assetEntries = new Map<String, DevFSContent>.from(assetBundle.entries);
-  final String vmSnapshotData = artifacts.getArtifactPath(Artifact.vmSnapshotData);
-  final String isolateSnapshotData = artifacts.getArtifactPath(Artifact.isolateSnapshotData);
 
   if (kernelContent != null) {
     final String platformKernelDill = artifacts.getArtifactPath(Artifact.platformKernelDill);
+    final String vmSnapshotData = artifacts.getArtifactPath(Artifact.vmSnapshotData);
+    final String isolateSnapshotData = artifacts.getArtifactPath(Artifact.isolateSnapshotData);
     assetEntries[_kKernelKey] = kernelContent;
     assetEntries[_kPlatformKernelKey] = new DevFSFileContent(fs.file(platformKernelDill));
     assetEntries[_kVMSnapshotData] = new DevFSFileContent(fs.file(vmSnapshotData));
     assetEntries[_kIsolateSnapshotData] = new DevFSFileContent(fs.file(isolateSnapshotData));
   }
-  if (snapshotFile != null) {
-    assetEntries[_kSnapshotKey] = new DevFSFileContent(snapshotFile);
-    assetEntries[_kVMSnapshotData] = new DevFSFileContent(fs.file(vmSnapshotData));
-    assetEntries[_kIsolateSnapshotData] = new DevFSFileContent(fs.file(isolateSnapshotData));
-  }
   if (dylibFile != null)
     assetEntries[_kDylibKey] = new DevFSFileContent(dylibFile);
 

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

@@ -26,8 +26,6 @@ class AnalyzeCommand extends FlutterCommand {
     argParser.addFlag('watch',
         help: 'Run analysis continuously, watching the filesystem for changes.',
         negatable: false);
-    argParser.addFlag('preview-dart-2',
-        defaultsTo: true, help: 'Preview Dart 2.0 functionality.');
     argParser.addOption('write',
         valueHelp: 'file',
         help: 'Also output the results to a file. This is useful with --watch '
@@ -87,7 +85,6 @@ class AnalyzeCommand extends FlutterCommand {
         argResults,
         runner.getRepoRoots(),
         runner.getRepoPackages(),
-        previewDart2: argResults['preview-dart-2'],
       ).analyze();
     } else {
       return new AnalyzeOnce(
@@ -95,7 +92,6 @@ class AnalyzeCommand extends FlutterCommand {
         runner.getRepoRoots(),
         runner.getRepoPackages(),
         workingDirectory: workingDirectory,
-        previewDart2: argResults['preview-dart-2'],
       ).analyze();
     }
   }

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

@@ -19,13 +19,10 @@ import '../globals.dart';
 import 'analyze_base.dart';
 
 class AnalyzeContinuously extends AnalyzeBase {
-  AnalyzeContinuously(ArgResults argResults, this.repoRoots, this.repoPackages, {
-    this.previewDart2 = false,
-  }) : super(argResults);
+  AnalyzeContinuously(ArgResults argResults, this.repoRoots, this.repoPackages) : super(argResults);
 
   final List<String> repoRoots;
   final List<Directory> repoPackages;
-  final bool previewDart2;
 
   String analysisTarget;
   bool firstAnalysis = true;
@@ -60,7 +57,7 @@ class AnalyzeContinuously extends AnalyzeBase {
 
     final String sdkPath = argResults['dart-sdk'] ?? sdk.dartSdkPath;
 
-    final AnalysisServer server = new AnalysisServer(sdkPath, directories, previewDart2: previewDart2);
+    final AnalysisServer server = new AnalysisServer(sdkPath, directories);
     server.onAnalyzing.listen((bool isAnalyzing) => _handleAnalysisStatus(server, isAnalyzing));
     server.onErrors.listen(_handleAnalysisErrors);
 

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

@@ -24,7 +24,6 @@ class AnalyzeOnce extends AnalyzeBase {
     this.repoRoots,
     this.repoPackages, {
     this.workingDirectory,
-    this.previewDart2 = false,
   }) : super(argResults);
 
   final List<String> repoRoots;
@@ -33,8 +32,6 @@ class AnalyzeOnce extends AnalyzeBase {
   /// The working directory for testing analysis using dartanalyzer.
   final Directory workingDirectory;
 
-  final bool previewDart2;
-
   @override
   Future<Null> analyze() async {
     final String currentDirectory =
@@ -91,7 +88,6 @@ class AnalyzeOnce extends AnalyzeBase {
     final AnalysisServer server = new AnalysisServer(
       sdkPath,
       directories.toList(),
-      previewDart2: previewDart2,
     );
 
     StreamSubscription<bool> subscription;

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

@@ -28,11 +28,6 @@ class BuildAotCommand extends BuildSubCommand {
         allowed: <String>['android-arm', 'android-arm64', 'ios']
       )
       ..addFlag('quiet', defaultsTo: false)
-      ..addFlag('preview-dart-2',
-        defaultsTo: true,
-        hide: !verboseHelp,
-        help: 'Preview Dart 2.0 functionality.',
-      )
       ..addFlag('build-shared-library',
         negatable: false,
         defaultsTo: false,
@@ -79,23 +74,20 @@ class BuildAotCommand extends BuildSubCommand {
     }
     final String outputPath = argResults['output-dir'] ?? getAotBuildDirectory();
     try {
-      final bool previewDart2 = argResults['preview-dart-2'];
       String mainPath = findMainDartFile(targetFile);
       final AOTSnapshotter snapshotter = new AOTSnapshotter();
 
-      // Compile to kernel, if Dart 2.
-      if (previewDart2) {
-        mainPath = await snapshotter.compileKernel(
-          platform: platform,
-          buildMode: buildMode,
-          mainPath: mainPath,
-          outputPath: outputPath,
-          extraFrontEndOptions: argResults[FlutterOptions.kExtraFrontEndOptions],
-        );
-        if (mainPath == null) {
-          printError('Compiler terminated unexpectedly.');
-          return;
-        }
+      // Compile to kernel.
+      mainPath = await snapshotter.compileKernel(
+        platform: platform,
+        buildMode: buildMode,
+        mainPath: mainPath,
+        outputPath: outputPath,
+        extraFrontEndOptions: argResults[FlutterOptions.kExtraFrontEndOptions],
+      );
+      if (mainPath == null) {
+        printError('Compiler terminated unexpectedly.');
+        return;
       }
 
       // Build AOT snapshot.
@@ -116,7 +108,6 @@ class BuildAotCommand extends BuildSubCommand {
             mainPath: mainPath,
             packagesPath: PackageMap.globalPackagesPath,
             outputPath: outputPath,
-            previewDart2: previewDart2,
             buildSharedLibrary: false,
             extraGenSnapshotOptions: argResults[FlutterOptions.kExtraGenSnapshotOptions],
           ).then((int buildExitCode) {
@@ -143,7 +134,6 @@ class BuildAotCommand extends BuildSubCommand {
           mainPath: mainPath,
           packagesPath: PackageMap.globalPackagesPath,
           outputPath: outputPath,
-          previewDart2: previewDart2,
           buildSharedLibrary: argResults['build-shared-library'],
           extraGenSnapshotOptions: argResults[FlutterOptions.kExtraGenSnapshotOptions],
         );

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

@@ -17,11 +17,6 @@ class BuildApkCommand extends BuildSubCommand {
     usesBuildNameOption();
 
     argParser
-      ..addFlag('preview-dart-2',
-        defaultsTo: true,
-        hide: !verboseHelp,
-        help: 'Preview Dart 2.0 functionality.',
-      )
       ..addFlag('track-widget-creation', negatable: false, hide: !verboseHelp)
       ..addFlag('build-shared-library',
         negatable: false,

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

@@ -19,14 +19,8 @@ class BuildBundleCommand extends BuildSubCommand {
       ..addOption('asset-base', help: 'Ignored. Will be removed.', hide: !verboseHelp)
       ..addOption('manifest', defaultsTo: defaultManifestPath)
       ..addOption('private-key', defaultsTo: defaultPrivateKeyPath)
-      ..addOption('snapshot', defaultsTo: defaultSnapshotPath)
       ..addOption('depfile', defaultsTo: defaultDepfilePath)
       ..addOption('kernel-file', defaultsTo: defaultApplicationKernelPath)
-      ..addFlag('preview-dart-2',
-        defaultsTo: true,
-        hide: !verboseHelp,
-        help: 'Preview Dart 2.0 functionality.',
-      )
       ..addFlag('track-widget-creation',
         hide: !verboseHelp,
         help: 'Track widget creation locations. Requires Dart 2.0 functionality.',
@@ -72,12 +66,10 @@ class BuildBundleCommand extends BuildSubCommand {
     await build(
       mainPath: targetFile,
       manifestPath: argResults['manifest'],
-      snapshotPath: argResults['snapshot'],
       applicationKernelFilePath: argResults['kernel-file'],
       depfilePath: argResults['depfile'],
       privateKeyPath: argResults['private-key'],
       assetDirPath: argResults['asset-dir'],
-      previewDart2: argResults['preview-dart-2'],
       precompiledSnapshot: argResults['precompiled'],
       reportLicensedPackages: argResults['report-licensed-packages'],
       trackWidgetCreation: argResults['track-widget-creation'],

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

@@ -38,11 +38,7 @@ class BuildIOSCommand extends BuildSubCommand {
       ..addFlag('codesign',
         defaultsTo: true,
         help: 'Codesign the application bundle (only available on device builds).',
-      )
-      ..addFlag('preview-dart-2',
-        defaultsTo: true,
-        hide: !verboseHelp,
-        help: 'Preview Dart 2.0 functionality.');
+      );
   }
 
   @override

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

@@ -334,7 +334,6 @@ class AppDomain extends Domain {
     final BuildInfo buildInfo = new BuildInfo(
       getBuildModeForName(mode) ?? BuildMode.debug,
       flavor,
-      previewDart2: _getBoolArg(args, 'preview-dart-2'),
     );
     DebuggingOptions options;
     if (buildInfo.isRelease) {
@@ -385,7 +384,6 @@ class AppDomain extends Domain {
 
     final FlutterDevice flutterDevice = new FlutterDevice(
       device,
-      previewDart2: options.buildInfo.previewDart2,
       trackWidgetCreation: trackWidgetCreation,
       dillOutputPath: dillOutputPath,
     );

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

@@ -62,10 +62,7 @@ class DriveCommand extends RunCommandBase {
               'just before the extension, so e.g. if the target is "lib/main.dart", the\n'
               'driver will be "test_driver/main_test.dart".',
         valueHelp: 'path',
-      )
-      ..addFlag('preview-dart-2',
-        defaultsTo: true,
-        help: 'Preview Dart 2.0 functionality.');
+      );
   }
 
   @override
@@ -123,7 +120,7 @@ class DriveCommand extends RunCommandBase {
     Cache.releaseLockEarly();
 
     try {
-      await testRunner(<String>[testFile], observatoryUri, argResults['preview-dart-2']);
+      await testRunner(<String>[testFile], observatoryUri);
     } catch (error, stackTrace) {
       if (error is ToolExit)
         rethrow;
@@ -275,24 +272,20 @@ Future<LaunchResult> _startApp(DriveCommand command) async {
 }
 
 /// Runs driver tests.
-typedef Future<Null> TestRunner(List<String> testArgs, String observatoryUri, bool previewDart2);
+typedef Future<Null> TestRunner(List<String> testArgs, String observatoryUri);
 TestRunner testRunner = _runTests;
 void restoreTestRunner() {
   testRunner = _runTests;
 }
 
-Future<Null> _runTests(List<String> testArgs, String observatoryUri, bool previewDart2) async {
+Future<Null> _runTests(List<String> testArgs, String observatoryUri) async {
   printTrace('Running driver tests.');
 
   PackageMap.globalPackagesPath = fs.path.normalize(fs.path.absolute(PackageMap.globalPackagesPath));
   final List<String> args = testArgs.toList()
     ..add('--packages=${PackageMap.globalPackagesPath}')
-    ..add('-rexpanded');
-  if (previewDart2) {
-    args.add('--preview-dart-2');
-  } else {
-    args.add('--no-preview-dart-2');
-  }
+    ..add('-rexpanded')
+    ..add('--preview-dart-2');
 
   final String dartVmPath = fs.path.join(dartSdkPath, 'bin', 'dart');
   final int result = await runCommandAndStreamOutput(

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

@@ -53,10 +53,6 @@ class FuchsiaReloadCommand extends FlutterCommand {
     argParser.addOption('name-override',
       abbr: 'n',
       help: 'On-device name of the application binary.');
-    argParser.addFlag('preview-dart-2',
-      abbr: '2',
-      defaultsTo: false,
-      help: 'Preview Dart 2.0 functionality.');
     argParser.addOption('target',
       abbr: 't',
       defaultsTo: bundle.defaultMainPath,
@@ -132,13 +128,8 @@ class FuchsiaReloadCommand extends FlutterCommand {
       final List<Uri> observatoryUris = fullAddresses.map(
         (String a) => Uri.parse('http://$a')
       ).toList();
-      final FuchsiaDevice device = new FuchsiaDevice(
-          fullAddresses[0], name: _address);
-      final FlutterDevice flutterDevice = new FlutterDevice(
-        device,
-        trackWidgetCreation: false,
-        previewDart2: false,
-      );
+      final FuchsiaDevice device = new FuchsiaDevice(fullAddresses[0], name: _address);
+      final FlutterDevice flutterDevice = new FlutterDevice(device, trackWidgetCreation: false);
       flutterDevice.observatoryUris = observatoryUris;
       final HotRunner hotRunner = new HotRunner(
         <FlutterDevice>[flutterDevice],

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

@@ -120,11 +120,6 @@ class RunCommand extends RunCommandBase {
         hide: !verboseHelp,
         help: 'Specify a pre-built application binary to use when running.',
       )
-      ..addFlag('preview-dart-2',
-        defaultsTo: true,
-        hide: !verboseHelp,
-        help: 'Preview Dart 2.0 functionality.',
-      )
       ..addFlag('track-widget-creation',
         hide: !verboseHelp,
         help: 'Track widget creation locations. Requires Dart 2.0 functionality.',
@@ -347,7 +342,6 @@ class RunCommand extends RunCommandBase {
     final List<FlutterDevice> flutterDevices = devices.map((Device device) {
       return new FlutterDevice(
         device,
-        previewDart2: argResults['preview-dart-2'],
         trackWidgetCreation: argResults['track-widget-creation'],
         dillOutputPath: argResults['output-dill'],
         fileSystemRoots: argResults['filesystem-root'],

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

@@ -68,11 +68,6 @@ class TestCommand extends FlutterCommand {
         help: 'Handle machine structured JSON command input\n'
               'and provide output and progress in machine friendly format.',
       )
-      ..addFlag('preview-dart-2',
-        defaultsTo: true,
-        hide: !verboseHelp,
-        help: 'Preview Dart 2.0 functionality.',
-      )
       ..addFlag('track-widget-creation',
         negatable: false,
         hide: !verboseHelp,
@@ -223,7 +218,6 @@ class TestCommand extends FlutterCommand {
       startPaused: startPaused,
       ipv6: argResults['ipv6'],
       machine: machine,
-      previewDart2: argResults['preview-dart-2'],
       trackWidgetCreation: argResults['track-widget-creation'],
       updateGoldens: argResults['update-goldens'],
     );

packages/flutter_tools/lib/src/dart/analysis.dart

@@ -13,11 +13,10 @@ import '../base/process_manager.dart';
 import '../globals.dart';
 
 class AnalysisServer {
-  AnalysisServer(this.sdkPath, this.directories, {this.previewDart2 = false});
+  AnalysisServer(this.sdkPath, this.directories);
 
   final String sdkPath;
   final List<String> directories;
-  final bool previewDart2;
 
   Process _process;
   final StreamController<bool> _analyzingController =
@@ -35,14 +34,9 @@ class AnalysisServer {
       snapshot,
       '--sdk',
       sdkPath,
+      '--preview-dart-2',
     ];
 
-    if (previewDart2) {
-      command.add('--preview-dart-2');
-    } else {
-      command.add('--no-preview-dart-2');
-    }
-
     printTrace('dart ${command.skip(1).join(' ')}');
     _process = await processManager.start(command);
     // This callback hookup can't throw.

packages/flutter_tools/lib/src/devfs.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert' show base64, utf8;
 
 import 'package:json_rpc_2/json_rpc_2.dart' as rpc;
+import 'package:meta/meta.dart';
 
 import 'asset.dart';
 import 'base/context.dart';
@@ -401,14 +402,14 @@ class DevFS {
   ///
   /// Returns the number of bytes synced.
   Future<int> update({
-    String mainPath,
+    @required String mainPath,
     String target,
     AssetBundle bundle,
     DateTime firstBuildTime,
     bool bundleFirstUpload = false,
     bool bundleDirty = false,
     Set<String> fileFilter,
-    ResidentCompiler generator,
+    @required ResidentCompiler generator,
     String dillOutputPath,
     bool fullRestart = false,
     String projectRootPath,
@@ -424,10 +425,9 @@ class DevFS {
     await _scanDirectory(rootDirectory,
                          recursive: true,
                          fileFilter: fileFilter);
-    final bool previewDart2 = generator != null;
     if (fs.isFileSync(_packagesFilePath)) {
       printTrace('Scanning package files');
-      await _scanPackages(fileFilter, previewDart2);
+      await _scanPackages(fileFilter);
     }
     if (bundle != null) {
       printTrace('Scanning asset files');
@@ -468,10 +468,9 @@ class DevFS {
       String archivePath;
       if (deviceUri.path.startsWith(assetBuildDirPrefix))
         archivePath = deviceUri.path.substring(assetBuildDirPrefix.length);
-      // When doing full restart in preview-dart-2 mode, copy content so
-      // that isModified does not reset last check timestamp because we
-      // want to report all modified files to incremental compiler next time
-      // user does hot reload.
+      // When doing full restart in, copy content so that isModified does not
+      // reset last check timestamp because we want to report all modified
+      // files to incremental compiler next time user does hot reload.
       if (content.isModified || ((bundleDirty || bundleFirstUpload) && archivePath != null)) {
         dirtyEntries[deviceUri] = content;
         numBytes += content.size;
@@ -479,24 +478,24 @@ class DevFS {
           assetPathsToEvict.add(archivePath);
       }
     });
-    if (previewDart2) {
-      // We run generator even if [dirtyEntries] was empty because we want
-      // to keep logic of accepting/rejecting generator's output simple:
-      // we must accept/reject generator's output after every [update] call.
-      // Incremental run with no changes is supposed to be fast (considering
-      // that it is initiated by user key press).
-      final List<String> invalidatedFiles = <String>[];
-      final Set<Uri> filesUris = new Set<Uri>();
-      for (Uri uri in dirtyEntries.keys.toList()) {
-        if (!uri.path.startsWith(assetBuildDirPrefix)) {
-          final DevFSContent content = dirtyEntries[uri];
-          if (content is DevFSFileContent) {
-            filesUris.add(uri);
-            invalidatedFiles.add(content.file.uri.toString());
-            numBytes -= content.size;
-          }
+
+    // We run generator even if [dirtyEntries] was empty because we want to
+    // keep logic of accepting/rejecting generator's output simple: we must
+    // accept/reject generator's output after every [update] call.  Incremental
+    // run with no changes is supposed to be fast (considering that it is
+    // initiated by user key press).
+    final List<String> invalidatedFiles = <String>[];
+    final Set<Uri> filesUris = new Set<Uri>();
+    for (Uri uri in dirtyEntries.keys.toList()) {
+      if (!uri.path.startsWith(assetBuildDirPrefix)) {
+        final DevFSContent content = dirtyEntries[uri];
+        if (content is DevFSFileContent) {
+          filesUris.add(uri);
+          invalidatedFiles.add(content.file.uri.toString());
+          numBytes -= content.size;
         }
       }
+
       // No need to send source files because all compilation is done on the
       // host and result of compilation is single kernel file.
       filesUris.forEach(dirtyEntries.remove);
@@ -504,10 +503,12 @@ class DevFS {
       if (fullRestart) {
         generator.reset();
       }
-      final CompilerOutput compilerOutput =
-          await generator.recompile(mainPath, invalidatedFiles,
-              outputPath:  dillOutputPath ?? fs.path.join(getBuildDirectory(), 'app.dill'),
-              packagesFilePath : _packagesFilePath);
+      final CompilerOutput compilerOutput = await generator.recompile(
+        mainPath,
+        invalidatedFiles,
+        outputPath:  dillOutputPath ?? fs.path.join(getBuildDirectory(), 'app.dill'),
+        packagesFilePath : _packagesFilePath,
+      );
       final String compiledBinary = compilerOutput?.outputFilename;
       if (compiledBinary != null && compiledBinary.isNotEmpty) {
         final String entryUri = projectRootPath != null ?
@@ -697,7 +698,7 @@ class DevFS {
     );
   }
 
-  Future<Null> _scanPackages(Set<String> fileFilter, bool previewDart2) async {
+  Future<Null> _scanPackages(Set<String> fileFilter) async {
     StringBuffer sb;
     final PackageMap packageMap = new PackageMap(_packagesFilePath);
 
@@ -730,22 +731,6 @@ class DevFS {
         sb.writeln('$packageName:$directoryUriOnDevice');
       }
     }
-    if (previewDart2) {
-      // When in previewDart2 mode we don't update .packages-file entry
-      // so actual file will get invalidated in frontend.
-      // We don't need to synthesize device-correct .packages file because
-      // it is not going to be used on the device anyway - compilation
-      // is done on the host.
-      return;
-    }
-    if (sb != null) {
-      final DevFSContent content = _entries[fs.path.toUri('.packages')];
-      if (content is DevFSStringContent && content.string == sb.toString()) {
-        content._exists = true;
-        return;
-      }
-      _entries[fs.path.toUri('.packages')] = new DevFSStringContent(sb.toString());
-    }
   }
 }
 /// Converts a platform-specific file path to a platform-independent Uri path.

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

@@ -246,7 +246,6 @@ Future<XcodeBuildResult> buildXcodeProject({
     projectPath: fs.currentDirectory.path,
     buildInfo: buildInfo,
     targetOverride: targetOverride,
-    previewDart2: buildInfo.previewDart2,
   );
 
   if (hasPlugins()) {
@@ -428,7 +427,7 @@ Future<XcodeBuildResult> buildXcodeProject({
       outputDir = expectedOutputDirectory.replaceFirst('/$configuration-', '/');
       if (fs.isDirectorySync(outputDir)) {
         // Previous output directory might have incompatible artifacts
-        // (for example, kernel binary files produced from previous `--preview-dart-2` run).
+        // (for example, kernel binary files produced from previous run).
         fs.directory(outputDir).deleteSync(recursive: true);
       }
       copyDirectorySync(fs.directory(expectedOutputDirectory), fs.directory(outputDir));

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

@@ -362,7 +362,6 @@ class IOSSimulator extends Device {
     // The build mode for the simulator is always debug.
 
     final BuildInfo debugBuildInfo = new BuildInfo(BuildMode.debug, buildInfo.flavor,
-        previewDart2: buildInfo.previewDart2,
         trackWidgetCreation: buildInfo.trackWidgetCreation,
         extraFrontEndOptions: buildInfo.extraFrontEndOptions,
         extraGenSnapshotOptions: buildInfo.extraGenSnapshotOptions,
@@ -390,12 +389,10 @@ class IOSSimulator extends Device {
   }
 
   Future<Null> _sideloadUpdatedAssetsForInstalledApplicationBundle(ApplicationPackage app, BuildInfo buildInfo, String mainPath) {
-    // When running in previewDart2 mode, we still need to run compiler to
-    // produce kernel file for the application.
+    // Run compiler to produce kernel file for the application.
     return bundle.build(
       mainPath: mainPath,
-      precompiledSnapshot: !buildInfo.previewDart2,
-      previewDart2: buildInfo.previewDart2,
+      precompiledSnapshot: false,
       trackWidgetCreation: buildInfo.trackWidgetCreation,
     );
   }

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

@@ -42,7 +42,6 @@ Future<void> generateXcodeProperties(String projectPath) async {
       projectPath: projectPath,
       buildInfo: BuildInfo.debug,
       targetOverride: bundle.defaultMainPath,
-      previewDart2: false,
     );
   }
 }
@@ -55,7 +54,6 @@ Future<void> updateGeneratedXcodeProperties({
   @required String projectPath,
   @required BuildInfo buildInfo,
   String targetOverride,
-  @required bool previewDart2,
 }) async {
   final StringBuffer localsBuffer = new StringBuffer();
 
@@ -113,10 +111,6 @@ Future<void> updateGeneratedXcodeProperties({
     localsBuffer.writeln('ARCHS=$arch');
   }
 
-  if (previewDart2) {
-    localsBuffer.writeln('PREVIEW_DART_2=true');
-  }
-
   if (buildInfo.trackWidgetCreation) {
     localsBuffer.writeln('TRACK_WIDGET_CREATION=true');
   }

packages/flutter_tools/lib/src/resident_runner.dart

@@ -34,7 +34,7 @@ class FlutterDevice {
   List<VMService> vmServices;
   DevFS devFS;
   ApplicationPackage package;
-  ResidentCompiler generator;
+  final ResidentCompiler generator;
   String dillOutputPath;
   List<String> fileSystemRoots;
   String fileSystemScheme;
@@ -42,20 +42,15 @@ class FlutterDevice {
   StreamSubscription<String> _loggingSubscription;
 
   FlutterDevice(this.device, {
-    @required bool previewDart2,
     @required bool trackWidgetCreation,
     this.dillOutputPath,
     this.fileSystemRoots,
     this.fileSystemScheme,
-  }) {
-    if (previewDart2) {
-      generator = new ResidentCompiler(
-        artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath),
-        trackWidgetCreation: trackWidgetCreation,
-        fileSystemRoots: fileSystemRoots, fileSystemScheme: fileSystemScheme
-      );
-    }
-  }
+  }) : generator = new ResidentCompiler(
+      artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath),
+      trackWidgetCreation: trackWidgetCreation,
+      fileSystemRoots: fileSystemRoots,
+      fileSystemScheme: fileSystemScheme);
 
   String viewFilter;
 
@@ -412,9 +407,9 @@ class FlutterDevice {
 
   void updateReloadStatus(bool wasReloadSuccessful) {
     if (wasReloadSuccessful)
-      generator?.accept();
+      generator.accept();
     else
-      generator?.reject();
+      generator.reject();
   }
 }
 

packages/flutter_tools/lib/src/run_hot.dart

@@ -412,15 +412,11 @@ class HotRunner extends ResidentRunner {
     }
     // We are now running from source.
     _runningFromSnapshot = false;
-    final String launchPath = debuggingOptions.buildInfo.previewDart2
-        ? mainPath + '.dill'
-        : mainPath;
-    await _launchFromDevFS(launchPath);
+
+    await _launchFromDevFS('$mainPath.dill');
     restartTimer.stop();
-    printTrace('Restart performed in '
-        '${getElapsedAsMilliseconds(restartTimer.elapsed)}.');
-    // We are now running from sources.
-    _runningFromSnapshot = false;
+    printTrace('Restart performed in ${getElapsedAsMilliseconds(restartTimer.elapsed)}.');
+
     _addBenchmarkData('hotRestartMillisecondsToFrame',
         restartTimer.elapsed.inMilliseconds);
     flutterUsage.sendEvent('hot', 'restart');
@@ -510,14 +506,6 @@ class HotRunner extends ResidentRunner {
     }
   }
 
-  String _uriToRelativePath(Uri uri) {
-    final String path = uri.toString();
-    final String base = new Uri.file(projectRootPath).toString();
-    if (path.startsWith(base))
-      return path.substring(base.length + 1);
-    return path;
-  }
-
   Future<OperationResult> _reloadSources({ bool pause = false }) async {
     for (FlutterDevice device in flutterDevices) {
       for (FlutterView view in device.views) {
@@ -537,7 +525,6 @@ class HotRunner extends ResidentRunner {
     // 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 reportUnused = !debuggingOptions.buildInfo.previewDart2;
     final bool shouldReportReloadTime = !_runningFromSnapshot;
     final Stopwatch reloadTimer = new Stopwatch()..start();
 
@@ -551,10 +538,7 @@ class HotRunner extends ResidentRunner {
     String reloadMessage;
     final Stopwatch vmReloadTimer = new Stopwatch()..start();
     try {
-      final String entryPath = fs.path.relative(
-        debuggingOptions.buildInfo.previewDart2 ? mainPath + '.dill' : mainPath,
-        from: projectRootPath,
-      );
+      final String entryPath = fs.path.relative('$mainPath.dill', from: projectRootPath);
       final Completer<Map<String, dynamic>> retrieveFirstReloadReport = new Completer<Map<String, dynamic>>();
 
       int countExpectedReports = 0;
@@ -566,10 +550,7 @@ class HotRunner extends ResidentRunner {
         }
 
         // List has one report per Flutter view.
-        final List<Future<Map<String, dynamic>>> reports = device.reloadSources(
-          entryPath,
-          pause: pause
-        );
+        final List<Future<Map<String, dynamic>>> reports = device.reloadSources(entryPath, pause: pause);
         countExpectedReports += reports.length;
         Future.wait(reports).catchError((dynamic error) {
           return <Map<String, dynamic>>[error];
@@ -637,8 +618,8 @@ class HotRunner extends ResidentRunner {
     }
     // We are now running from source.
     _runningFromSnapshot = false;
-    // Check if the isolate is paused.
 
+    // Check if the isolate is paused.
     final List<FlutterView> reassembleViews = <FlutterView>[];
     for (FlutterDevice device in flutterDevices) {
       for (FlutterView view in device.views) {
@@ -699,36 +680,9 @@ class HotRunner extends ResidentRunner {
         shouldReportReloadTime)
       flutterUsage.sendTiming('hot', 'reload', reloadTimer.elapsed);
 
-    String unusedElementMessage;
-    if (reportUnused && !reassembleAndScheduleErrors && !reassembleTimedOut) {
-      final List<Future<List<ProgramElement>>> unusedReports =
-        <Future<List<ProgramElement>>>[];
-      for (FlutterDevice device in flutterDevices)
-        unusedReports.add(device.unusedChangesInLastReload());
-      final List<ProgramElement> unusedElements = <ProgramElement>[];
-      for (Future<List<ProgramElement>> unusedReport in unusedReports)
-        unusedElements.addAll(await unusedReport);
-
-      if (unusedElements.isNotEmpty) {
-        final String restartCommand = hostIsIde ? '' : ' (by pressing "R")';
-        unusedElementMessage =
-          'Some program elements were changed during reload but did not run when the view was reassembled;\n'
-          'you may need to restart the app$restartCommand for the changes to have an effect.';
-        for (ProgramElement unusedElement in unusedElements) {
-          final String name = unusedElement.qualifiedName;
-          final String path = _uriToRelativePath(unusedElement.uri);
-          final int line = unusedElement.line;
-          final String description = line == null ? '$name ($path)' : '$name ($path:$line)';
-          unusedElementMessage += '\n  • $description';
-        }
-      }
-    }
-
     return new OperationResult(
       reassembleAndScheduleErrors ? 1 : OperationResult.ok.code,
       reloadMessage,
-      hintMessage: unusedElementMessage,
-      hintId: unusedElementMessage != null ? 'restartRecommended' : null,
     );
   }
 

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

@@ -182,10 +182,6 @@ abstract class FlutterCommand extends Command<Null> {
   }
 
   BuildInfo getBuildInfo() {
-    final bool previewDart2 = argParser.options.containsKey('preview-dart-2')
-        ? argResults['preview-dart-2']
-        : true;
-
     TargetPlatform targetPlatform;
     if (argParser.options.containsKey('target-platform') &&
         argResults['target-platform'] != 'default') {
@@ -195,10 +191,6 @@ abstract class FlutterCommand extends Command<Null> {
     final bool trackWidgetCreation = argParser.options.containsKey('track-widget-creation')
         ? argResults['track-widget-creation']
         : false;
-    if (trackWidgetCreation == true && previewDart2 == false) {
-      throw new UsageException(
-          '--track-widget-creation is valid only when --preview-dart-2 is specified.', null);
-    }
 
     int buildNumber;
     try {
@@ -214,7 +206,6 @@ abstract class FlutterCommand extends Command<Null> {
       argParser.options.containsKey('flavor')
         ? argResults['flavor']
         : null,
-      previewDart2: previewDart2,
       trackWidgetCreation: trackWidgetCreation,
       extraFrontEndOptions: argParser.options.containsKey(FlutterOptions.kExtraFrontEndOptions)
           ? argResults[FlutterOptions.kExtraFrontEndOptions]

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

@@ -67,7 +67,6 @@ void installHook({
   bool enableObservatory = false,
   bool machine = false,
   bool startPaused = false,
-  bool previewDart2 = false,
   int port = 0,
   String precompiledDillPath,
   bool trackWidgetCreation = false,
@@ -86,7 +85,6 @@ void installHook({
       startPaused: startPaused,
       explicitObservatoryPort: observatoryPort,
       host: _kHosts[serverType],
-      previewDart2: previewDart2,
       port: port,
       precompiledDillPath: precompiledDillPath,
       trackWidgetCreation: trackWidgetCreation,
@@ -306,7 +304,6 @@ class _FlutterPlatform extends PlatformPlugin {
     this.startPaused,
     this.explicitObservatoryPort,
     this.host,
-    this.previewDart2,
     this.port,
     this.precompiledDillPath,
     this.trackWidgetCreation,
@@ -320,7 +317,6 @@ class _FlutterPlatform extends PlatformPlugin {
   final bool startPaused;
   final int explicitObservatoryPort;
   final InternetAddress host;
-  final bool previewDart2;
   final int port;
   final String precompiledDillPath;
   final bool trackWidgetCreation;
@@ -408,17 +404,15 @@ class _FlutterPlatform extends PlatformPlugin {
         cancelOnError: true,
       );
 
-      printTrace('test $ourTestCount: starting shell process${previewDart2? " in preview-dart-2 mode":""}');
+      printTrace('test $ourTestCount: starting shell process');
 
-      // [precompiledDillPath] can be set only if [previewDart2] is [true].
-      assert(precompiledDillPath == null || previewDart2);
       // If a kernel file is given, then use that to launch the test.
       // Otherwise create a "listener" dart that invokes actual test.
       String mainDart = precompiledDillPath != null
           ? precompiledDillPath
           : _createListenerDart(finalizers, ourTestCount, testPath, server);
 
-      if (previewDart2 && precompiledDillPath == null) {
+      if (precompiledDillPath == null) {
         // Lazily instantiate compiler so it is built only if it is actually used.
         compiler ??= new _Compiler(trackWidgetCreation);
         mainDart = await compiler.compile(mainDart);
@@ -675,10 +669,6 @@ class _FlutterPlatform extends PlatformPlugin {
   }
 
   String _getBundlePath(List<_Finalizer> finalizers, int ourTestCount) {
-    if (!previewDart2) {
-      return null;
-    }
-
     if (precompiledDillPath != null) {
       return artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath);
     }

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

@@ -4,7 +4,6 @@
 
 import 'dart:async';
 
-import 'package:args/command_runner.dart';
 // ignore: implementation_imports
 import 'package:test/src/executable.dart' as test;
 
@@ -29,18 +28,10 @@ Future<int> runTests(
     bool startPaused = false,
     bool ipv6 = false,
     bool machine = false,
-    bool previewDart2 = false,
     bool trackWidgetCreation = false,
     bool updateGoldens = false,
     TestWatcher watcher,
     }) async {
-  if (trackWidgetCreation && !previewDart2) {
-    throw new UsageException(
-      '--track-widget-creation is valid only when --preview-dart-2 is specified.',
-      null,
-    );
-  }
-
   // Compute the command-line arguments for package:test.
   final List<String> testArgs = <String>[];
   if (!terminal.supportsColor) {
@@ -87,7 +78,6 @@ Future<int> runTests(
     machine: machine,
     startPaused: startPaused,
     serverType: serverType,
-    previewDart2: previewDart2,
     trackWidgetCreation: trackWidgetCreation,
     updateGoldens: updateGoldens,
   );

packages/flutter_tools/lib/src/tester/flutter_tester.dart

@@ -133,20 +133,11 @@ class FlutterTesterDevice extends Device {
       mainPath: mainPath,
       assetDirPath: assetDirPath,
       applicationKernelFilePath: applicationKernelFilePath,
-      precompiledSnapshot: !buildInfo.previewDart2,
-      previewDart2: buildInfo.previewDart2,
+      precompiledSnapshot: false,
       trackWidgetCreation: buildInfo.trackWidgetCreation,
     );
-    if (buildInfo.previewDart2) {
-      mainPath = applicationKernelFilePath;
-    }
-
     command.add('--flutter-assets-dir=$assetDirPath');
-
-    // TODO(scheglov): Either remove the check, or make it fail earlier.
-    if (mainPath != null) {
-      command.add(mainPath);
-    }
+    command.add(applicationKernelFilePath);
 
     try {
       printTrace(command.join(' '));

packages/flutter_tools/test/commands/analyze_continuously_test.dart

@@ -70,10 +70,10 @@ void main() {
     OperatingSystemUtils: () => os
   });
 
-  testUsingContext('--preview-dart-2', () async {
+  testUsingContext('Returns no errors when source is error-free', () async {
     const String contents = "StringBuffer bar = StringBuffer('baz');";
     tempDir.childFile('main.dart').writeAsStringSync(contents);
-    server = new AnalysisServer(dartSdkPath, <String>[tempDir.path], previewDart2: true);
+    server = new AnalysisServer(dartSdkPath, <String>[tempDir.path]);
 
     int errorCount = 0;
     final Future<bool> onDone = server.onAnalyzing.where((bool analyzing) => analyzing == false).first;
@@ -88,25 +88,6 @@ void main() {
   }, overrides: <Type, Generator>{
     OperatingSystemUtils: () => os
   });
-
-  testUsingContext('no --preview-dart-2 shows errors', () async {
-    const String contents = "StringBuffer bar = StringBuffer('baz');";
-    tempDir.childFile('main.dart').writeAsStringSync(contents);
-    server = new AnalysisServer(dartSdkPath, <String>[tempDir.path], previewDart2: false);
-
-    int errorCount = 0;
-    final Future<bool> onDone = server.onAnalyzing.where((bool analyzing) => analyzing == false).first;
-    server.onErrors.listen((FileAnalysisErrors errors) {
-      errorCount += errors.errors.length;
-    });
-
-    await server.start();
-    await onDone;
-
-    expect(errorCount, 1);
-  }, overrides: <Type, Generator>{
-    OperatingSystemUtils: () => os
-  });
 }
 
 void _createSampleProject(Directory directory, { bool brokenCode = false }) {

packages/flutter_tools/test/commands/analyze_once_test.dart

@@ -168,7 +168,7 @@ void bar() {
       }
     });
 
-    testUsingContext('--preview-dart-2', () async {
+    testUsingContext('returns no issues when source is error-free', () async {
       const String contents = '''
 StringBuffer bar = StringBuffer('baz');
 ''';
@@ -179,33 +179,13 @@ StringBuffer bar = StringBuffer('baz');
       try {
         await runCommand(
           command: new AnalyzeCommand(workingDirectory: fs.directory(tempDir)),
-          arguments: <String>['analyze', '--preview-dart-2'],
+          arguments: <String>['analyze'],
           statusTextContains: <String>['No issues found!'],
         );
       } finally {
         tempDir.deleteSync(recursive: true);
       }
     });
-
-    testUsingContext('no --preview-dart-2 shows errors', () async {
-      const String contents = '''
-StringBuffer bar = StringBuffer('baz');
-''';
-
-      final Directory tempDir = fs.systemTempDirectory.createTempSync();
-      tempDir.childFile('main.dart').writeAsStringSync(contents);
-
-      try {
-        await runCommand(
-          command: new AnalyzeCommand(workingDirectory: fs.directory(tempDir)),
-          arguments: <String>['analyze', '--no-preview-dart-2'],
-          statusTextContains: <String>['1 issue found.'],
-          toolExit: true,
-        );
-      } finally {
-        tempDir.deleteSync(recursive: true);
-      }
-    });
   });
 }
 

packages/flutter_tools/test/commands/drive_test.dart

@@ -54,7 +54,7 @@ void main() {
       appStarter = (DriveCommand command) {
         throw 'Unexpected call to appStarter';
       };
-      testRunner = (List<String> testArgs, String observatoryUri, bool previewDart2) {
+      testRunner = (List<String> testArgs, String observatoryUri) {
         throw 'Unexpected call to testRunner';
       };
       appStopper = (DriveCommand command) {
@@ -169,7 +169,7 @@ void main() {
       appStarter = expectAsync1((DriveCommand command) async {
         return new LaunchResult.succeeded();
       });
-      testRunner = expectAsync3((List<String> testArgs, String observatoryUri, bool previewDart2) async {
+      testRunner = expectAsync2((List<String> testArgs, String observatoryUri) async {
         expect(testArgs, <String>[testFile]);
         return null;
       });
@@ -200,7 +200,7 @@ void main() {
       appStarter = expectAsync1((DriveCommand command) async {
         return new LaunchResult.succeeded();
       });
-      testRunner = (List<String> testArgs, String observatoryUri, bool previewDart2) async {
+      testRunner = (List<String> testArgs, String observatoryUri) async {
         throwToolExit(null, exitCode: 123);
       };
       appStopper = expectAsync1((DriveCommand command) async {

packages/flutter_tools/test/ios/xcodeproj_test.dart

@@ -284,14 +284,10 @@ Information about project "Runner":
     testUsingOsxContext('sets ARCHS=armv7 when armv7 local engine is set', () async {
       when(mockArtifacts.getArtifactPath(Artifact.flutterFramework, TargetPlatform.ios, typed(any))).thenReturn('engine');
       when(mockArtifacts.engineOutPath).thenReturn(fs.path.join('out', 'ios_profile_arm'));
-      const BuildInfo buildInfo = const BuildInfo(BuildMode.debug, null,
-        previewDart2: true,
-        targetPlatform: TargetPlatform.ios,
-      );
+      const BuildInfo buildInfo = const BuildInfo(BuildMode.debug, null, targetPlatform: TargetPlatform.ios);
       await updateGeneratedXcodeProperties(
         projectPath: 'path/to/project',
         buildInfo: buildInfo,
-        previewDart2: true,
       );
 
       final File config = fs.file('path/to/project/ios/Flutter/Generated.xcconfig');
@@ -305,14 +301,12 @@ Information about project "Runner":
       when(mockArtifacts.getArtifactPath(Artifact.flutterFramework, TargetPlatform.ios, typed(any))).thenReturn('engine');
       when(mockArtifacts.engineOutPath).thenReturn(fs.path.join('out', 'ios_profile_arm'));
       const BuildInfo buildInfo = const BuildInfo(BuildMode.debug, null,
-        previewDart2: true,
         trackWidgetCreation: true,
         targetPlatform: TargetPlatform.ios,
       );
       await updateGeneratedXcodeProperties(
         projectPath: 'path/to/project',
         buildInfo: buildInfo,
-        previewDart2: true,
       );
 
       final File config = fs.file('path/to/project/ios/Flutter/Generated.xcconfig');
@@ -325,14 +319,10 @@ Information about project "Runner":
     testUsingOsxContext('does not set TRACK_WIDGET_CREATION when trackWidgetCreation is false', () async {
       when(mockArtifacts.getArtifactPath(Artifact.flutterFramework, TargetPlatform.ios, typed(any))).thenReturn('engine');
       when(mockArtifacts.engineOutPath).thenReturn(fs.path.join('out', 'ios_profile_arm'));
-      const BuildInfo buildInfo = const BuildInfo(BuildMode.debug, null,
-        previewDart2: true,
-        targetPlatform: TargetPlatform.ios,
-      );
+      const BuildInfo buildInfo = const BuildInfo(BuildMode.debug, null, targetPlatform: TargetPlatform.ios);
       await updateGeneratedXcodeProperties(
         projectPath: 'path/to/project',
         buildInfo: buildInfo,
-        previewDart2: true,
       );
 
       final File config = fs.file('path/to/project/ios/Flutter/Generated.xcconfig');
@@ -345,14 +335,10 @@ Information about project "Runner":
     testUsingOsxContext('sets ARCHS=armv7 when armv7 local engine is set', () async {
       when(mockArtifacts.getArtifactPath(Artifact.flutterFramework, TargetPlatform.ios, typed(any))).thenReturn('engine');
       when(mockArtifacts.engineOutPath).thenReturn(fs.path.join('out', 'ios_profile'));
-      const BuildInfo buildInfo = const BuildInfo(BuildMode.debug, null,
-        previewDart2: true,
-        targetPlatform: TargetPlatform.ios,
-      );
+      const BuildInfo buildInfo = const BuildInfo(BuildMode.debug, null, targetPlatform: TargetPlatform.ios);
       await updateGeneratedXcodeProperties(
         projectPath: 'path/to/project',
         buildInfo: buildInfo,
-        previewDart2: true,
       );
 
       final File config = fs.file('path/to/project/ios/Flutter/Generated.xcconfig');
@@ -405,7 +391,6 @@ Information about project "Runner":
         projectPath: projectPath,
         buildInfo: buildInfo,
         targetOverride: bundle.defaultMainPath,
-        previewDart2: false,
       );
 
       final String propertiesPath = fs.path.join(projectPath, 'ios', 'Flutter', 'Generated.xcconfig');

packages/flutter_tools/test/resident_runner_test.dart

@@ -44,14 +44,11 @@ class TestRunner extends ResidentRunner {
 
 void main() {
   TestRunner createTestRunner() {
-    // TODO(jacobr): make these tests run with `previewDart2: true` and
-    // `trackWidgetCreation: true` as well as the default flags.
-    // Currently the TestRunner is not properly configured to be able to run
-    // with `previewDart2: true` due to missing resources.
+    // TODO(jacobr): make these tests run with `trackWidgetCreation: true` as
+    // well as the default flags.
     return new TestRunner(
       <FlutterDevice>[new FlutterDevice(
         new MockDevice(),
-        previewDart2: false,
         trackWidgetCreation: false,
       )],
     );

packages/flutter_tools/test/tester/flutter_tester_test.dart

@@ -6,11 +6,14 @@ import 'dart:async';
 
 import 'package:file/file.dart';
 import 'package:file/memory.dart';
+import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/cache.dart';
+import 'package:flutter_tools/src/compile.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/tester/flutter_tester.dart';
+import 'package:mockito/mockito.dart';
 import 'package:process/process.dart';
 import 'package:test/test.dart';
 
@@ -97,6 +100,8 @@ void main() {
       String projectPath;
       String mainPath;
 
+      MockArtifacts mockArtifacts;
+      MockKernelCompiler mockKernelCompiler;
       MockProcessManager mockProcessManager;
       MockProcess mockProcess;
 
@@ -105,6 +110,8 @@ void main() {
         FileSystem: () => fs,
         Cache: () => new Cache(rootOverride: fs.directory(flutterRoot)),
         ProcessManager: () => mockProcessManager,
+        KernelCompiler: () => mockKernelCompiler,
+        Artifacts: () => mockArtifacts,
       };
 
       setUp(() {
@@ -122,6 +129,13 @@ void main() {
         mockProcessManager = new MockProcessManager();
         mockProcessManager.processFactory =
             (List<String> commands) => mockProcess;
+
+        mockArtifacts = new MockArtifacts();
+        final String artifactPath = fs.path.join(flutterRoot, 'artifact');
+        fs.file(artifactPath).createSync(recursive: true);
+        when(mockArtifacts.getArtifactPath(any)).thenReturn(artifactPath);
+
+        mockKernelCompiler = new MockKernelCompiler();
       });
 
       testUsingContext('not debug', () async {
@@ -153,6 +167,22 @@ Hello!
               .codeUnits
         ]));
 
+        when(mockKernelCompiler.compile(
+          sdkRoot: any,
+          incrementalCompilerByteStorePath: any,
+          mainPath: any,
+          outputFilePath: any,
+          depFilePath: any,
+          trackWidgetCreation: any,
+          extraFrontEndOptions: any,
+          fileSystemRoots: any,
+          fileSystemScheme: any,
+          packagesPath: any,
+        )).thenAnswer((_) async {
+          fs.file('$mainPath.dill').createSync(recursive: true);
+          return new CompilerOutput('$mainPath.dill', 0);
+        });
+
         final LaunchResult result = await device.startApp(null,
             mainPath: mainPath,
             debuggingOptions: new DebuggingOptions.enabled(
@@ -165,3 +195,6 @@ Hello!
     });
   });
 }
+
+class MockArtifacts extends Mock implements Artifacts {}
+class MockKernelCompiler extends Mock implements KernelCompiler {}