prefer const constructor (#8292)

packages/flutter/test/widgets/positioned_test.dart

@@ -40,7 +40,7 @@ void main() {
     expect(b.width, 100.0);
     expect(b.height, 200.0);
     Positioned c = new Positioned.fromRelativeRect(
-      rect: new RelativeRect.fromLTRB(
+      rect: const RelativeRect.fromLTRB(
         103.0,
         303.0,
         203.0,

packages/flutter_markdown/lib/src/markdown_raw.dart

@@ -249,7 +249,7 @@ class _Renderer implements md.NodeVisitor {
         linkInfo = _linkHandler.createLinkInfo(element.attributes['href']);
       }
 
-      TextStyle style = _markdownStyle.styles[element.tag] ?? new TextStyle();
+      TextStyle style = _markdownStyle.styles[element.tag] ?? const TextStyle();
       List<_MarkdownNode> styleElement = <_MarkdownNode>[new _MarkdownNodeTextStyle(style, linkInfo)];
       _currentBlock.stack.add(new _MarkdownNodeList(styleElement));
     }
@@ -338,7 +338,7 @@ class _Block {
   _Block(this.tag, this.attributes, this.markdownStyle, this.listIndents, this.blockPosition) {
     TextStyle style = markdownStyle.styles[tag];
     if (style == null)
-      style = new TextStyle(color: const Color(0xffff0000));
+      style = const TextStyle(color: const Color(0xffff0000));
 
     stack = <_MarkdownNode>[new _MarkdownNodeList(<_MarkdownNode>[new _MarkdownNodeTextStyle(style)])];
     subBlocks = <_Block>[];
@@ -398,7 +398,7 @@ class _Block {
         }
         else {
           bullet = new Padding(
-            padding: new EdgeInsets.only(right: 5.0),
+            padding: const EdgeInsets.only(right: 5.0),
             child: new Text(
               "${blockPosition + 1}.",
               textAlign: TextAlign.right

packages/flutter_markdown/lib/src/markdown_style.dart

@@ -25,8 +25,8 @@ class MarkdownStyle extends MarkdownStyleRaw{
     h4: theme.textTheme.body2,
     h5: theme.textTheme.body2,
     h6: theme.textTheme.body2,
-    em: new TextStyle(fontStyle: FontStyle.italic),
-    strong: new TextStyle(fontWeight: FontWeight.bold),
+    em: const TextStyle(fontStyle: FontStyle.italic),
+    strong: const TextStyle(fontWeight: FontWeight.bold),
     blockquote: theme.textTheme.body1,
     blockSpacing: 8.0,
     listIndent: 32.0,
@@ -59,8 +59,8 @@ class MarkdownStyle extends MarkdownStyleRaw{
     h4: theme.textTheme.headline,
     h5: theme.textTheme.title,
     h6: theme.textTheme.subhead,
-    em: new TextStyle(fontStyle: FontStyle.italic),
-    strong: new TextStyle(fontWeight: FontWeight.bold),
+    em: const TextStyle(fontStyle: FontStyle.italic),
+    strong: const TextStyle(fontWeight: FontWeight.bold),
     blockquote: theme.textTheme.body1,
     blockSpacing: 8.0,
     listIndent: 32.0,

packages/flutter_tools/bin/fuchsia_builder.dart

@@ -39,9 +39,9 @@ Future<Null> main(List<String> args) async {
   executableContext.setVariable(Logger, new StdoutLogger());
   executableContext.runInZone(() {
     // Initialize the context with some defaults.
-    context.putIfAbsent(Platform, () => new LocalPlatform());
-    context.putIfAbsent(FileSystem, () => new LocalFileSystem());
-    context.putIfAbsent(ProcessManager, () => new LocalProcessManager());
+    context.putIfAbsent(Platform, () => const LocalPlatform());
+    context.putIfAbsent(FileSystem, () => const LocalFileSystem());
+    context.putIfAbsent(ProcessManager, () => const LocalProcessManager());
     context.putIfAbsent(Logger, () => new StdoutLogger());
     context.putIfAbsent(Cache, () => new Cache());
     context.putIfAbsent(Config, () => new Config());

packages/flutter_tools/lib/executable.dart

@@ -102,9 +102,9 @@ Future<Null> main(List<String> args) async {
     // in those locations as well to see if you need a similar update there.
 
     // Seed these context entries first since others depend on them
-    context.putIfAbsent(Platform, () => new LocalPlatform());
-    context.putIfAbsent(FileSystem, () => new LocalFileSystem());
-    context.putIfAbsent(ProcessManager, () => new LocalProcessManager());
+    context.putIfAbsent(Platform, () => const LocalPlatform());
+    context.putIfAbsent(FileSystem, () => const LocalFileSystem());
+    context.putIfAbsent(ProcessManager, () => const LocalProcessManager());
     context.putIfAbsent(Logger, () => platform.isWindows ? new WindowsStdoutLogger() : new StdoutLogger());
     context.putIfAbsent(Config, () => new Config());
 

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

@@ -459,7 +459,7 @@ class AndroidDevice extends Device {
       'shell', 'am', 'broadcast', '-a', 'io.flutter.view.DISCOVER'
     ]));
 
-    return new Future<List<DiscoveredApp>>.delayed(new Duration(seconds: 1), () {
+    return new Future<List<DiscoveredApp>>.delayed(const Duration(seconds: 1), () {
       logs.cancel();
       return result;
     });

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

@@ -37,7 +37,7 @@ class Config {
   }
 
   void _flushValues() {
-    String json = new JsonEncoder.withIndent('  ').convert(_values);
+    String json = const JsonEncoder.withIndent('  ').convert(_values);
     json = '$json\n';
     _configFile.writeAsStringSync(json);
   }

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

@@ -295,7 +295,7 @@ class _AnsiStatus extends Status {
     stdout.write('${message.padRight(52)}     ');
     stdout.write('${_progress[0]}');
 
-    timer = new Timer.periodic(new Duration(milliseconds: 100), _callback);
+    timer = new Timer.periodic(const Duration(milliseconds: 100), _callback);
   }
 
   static final List<String> _progress = <String>['-', r'\', '|', r'/', '-', r'\', '|', '/'];

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

@@ -29,7 +29,7 @@ ProcessManager get processManager => context[ProcessManager];
 /// subdirectory.
 void enableRecordingProcessManager(String location) {
   Directory dir = getRecordingSink(location, _kRecordingType);
-  ProcessManager delegate = new LocalProcessManager();
+  ProcessManager delegate = const LocalProcessManager();
   RecordingProcessManager manager = new RecordingProcessManager(delegate, dir);
   addShutdownHook(() => manager.flush(finishRunningProcesses: true));
   context.setVariable(ProcessManager, manager);

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

@@ -73,7 +73,7 @@ File getUniqueFile(Directory dir, String baseName, String ext) {
 }
 
 String toPrettyJson(Object jsonable) {
-  return new JsonEncoder.withIndent('  ').convert(jsonable) + '\n';
+  return const JsonEncoder.withIndent('  ').convert(jsonable) + '\n';
 }
 
 /// Return a String - with units - for the size in MB of the given number of bytes.

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

@@ -464,7 +464,7 @@ class AppDomain extends Domain {
     if (app == null)
       throw "app '$appId' not found";
 
-    return app.stop().timeout(new Duration(seconds: 5)).then<bool>((_) {
+    return app.stop().timeout(const Duration(seconds: 5)).then<bool>((_) {
       return true;
     }).catchError((dynamic error) {
       _sendAppEvent(app, 'log', <String, dynamic>{ 'log': '$error', 'error': true });

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

@@ -97,7 +97,7 @@ class TestCommand extends FlutterCommand {
   Future<bool> _collectCoverageData(CoverageCollector collector, { bool mergeCoverageData: false }) async {
     Status status = logger.startProgress('Collecting coverage information...');
     String coverageData = await collector.finalizeCoverage(
-      timeout: new Duration(seconds: 30),
+      timeout: const Duration(seconds: 30),
     );
     status.stop();
     printTrace('coverage information collection complete');

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

@@ -83,7 +83,7 @@ class SimControl {
       connected = _isAnyConnected();
       if (!connected) {
         printStatus('Still waiting for iOS Simulator to boot...');
-        await new Future<Null>.delayed(new Duration(seconds: 1));
+        await new Future<Null>.delayed(const Duration(seconds: 1));
       }
       attempted++;
     }

packages/flutter_tools/lib/src/resident_runner.dart

@@ -218,7 +218,7 @@ abstract class ResidentRunner {
     for (int i = 0; vmService.vm.mainView == null && i < 5; i++) {
       // If the VM doesn't yet have a view, wait for one to show up.
       printTrace('Waiting for Flutter view');
-      await new Future<Null>.delayed(new Duration(seconds: 1));
+      await new Future<Null>.delayed(const Duration(seconds: 1));
       await vmService.vm.refreshViews();
     }
     currentView = vmService.vm.mainView;
@@ -354,7 +354,7 @@ abstract class ResidentRunner {
       if ((currentView != null) && (currentView.uiIsolate != null)) {
         // TODO(johnmccutchan): Wait for the exit command to complete.
         currentView.uiIsolate.flutterExit();
-        await new Future<Null>.delayed(new Duration(milliseconds: 100));
+        await new Future<Null>.delayed(const Duration(milliseconds: 100));
       }
     }
     appFinished();

packages/flutter_tools/lib/src/run_hot.dart

@@ -314,7 +314,7 @@ class HotRunner extends ResidentRunner {
     if (_devFS != null) {
       // Cleanup the devFS; don't wait indefinitely, and ignore any errors.
       await _devFS.destroy()
-        .timeout(new Duration(milliseconds: 250))
+        .timeout(const Duration(milliseconds: 250))
         .catchError((dynamic error) {
           printTrace('$error');
         });

packages/flutter_tools/lib/src/usage.dart

@@ -96,7 +96,7 @@ class Usage {
     // TODO(devoncarew): This may delay tool exit and could cause some analytics
     // events to not be reported. Perhaps we could send the analytics pings
     // out-of-process from flutter_tools?
-    await _analytics.waitForLastPing(timeout: new Duration(milliseconds: 250));
+    await _analytics.waitForLastPing(timeout: const Duration(milliseconds: 250));
   }
 
   void printUsage() {

packages/flutter_tools/test/asset_bundle_test.dart

@@ -10,7 +10,7 @@ import 'package:test/test.dart';
 
 void main()  {
   // Create a temporary directory and write a single file into it.
-  FileSystem fs = new LocalFileSystem();
+  FileSystem fs = const LocalFileSystem();
   Directory tempDir = fs.systemTempDirectory.createTempSync();
   String projectRoot = tempDir.path;
   String assetPath = 'banana.txt';

packages/flutter_tools/test/daemon_test.dart

@@ -32,7 +32,7 @@ void main() {
     setUp(() {
       appContext = new AppContext();
       notifyingLogger = new NotifyingLogger();
-      appContext.setVariable(Platform, new LocalPlatform());
+      appContext.setVariable(Platform, const LocalPlatform());
       appContext.setVariable(Logger, notifyingLogger);
       appContext.setVariable(Doctor, new Doctor());
       if (platform.isMacOS)

packages/flutter_tools/test/dependency_checker_test.dart

@@ -88,7 +88,7 @@ void main()  {
       String destinationPath = '/some/test/location';
       // Copy the golden input and let the test run in an isolated temporary in-memory file system.
       copyDirectorySync(
-        new LocalFileSystem().directory(fs.path.join(dataPath, 'changed_sdk_location')),
+        const LocalFileSystem().directory(fs.path.join(dataPath, 'changed_sdk_location')),
         fs.directory(destinationPath));
       fs.currentDirectory = destinationPath;
 

packages/flutter_tools/test/devfs_test.dart

@@ -236,7 +236,7 @@ void main() {
       ]);
       expect(devFS.assetPathsToEvict, isEmpty);
       expect(bytes, 31);
-    }, timeout: new Timeout(new Duration(seconds: 5)));
+    }, timeout: const Timeout(const Duration(seconds: 5)));
 
     testUsingContext('delete dev file system', () async {
       await devFS.destroy();
@@ -340,4 +340,4 @@ Future<Null> _createPackage(String pkgName, String pkgFileName) async {
   fs.file(fs.path.join(_tempDirs[0].path, '.packages')).writeAsStringSync(sb.toString());
 }
 
-String _inAssetBuildDirectory(String filename) => fs.path.join(getAssetBuildDirectory(), filename);
\ No newline at end of file
+String _inAssetBuildDirectory(String filename) => fs.path.join(getAssetBuildDirectory(), filename);

packages/flutter_tools/test/src/context.dart

@@ -42,9 +42,9 @@ void testUsingContext(String description, dynamic testMethod(), {
 
     // Initialize the test context with some default mocks.
     // Seed these context entries first since others depend on them
-    testContext.putIfAbsent(Platform, () => new LocalPlatform());
-    testContext.putIfAbsent(FileSystem, () => new LocalFileSystem());
-    testContext.putIfAbsent(ProcessManager, () => new LocalProcessManager());
+    testContext.putIfAbsent(Platform, () => const LocalPlatform());
+    testContext.putIfAbsent(FileSystem, () => const LocalFileSystem());
+    testContext.putIfAbsent(ProcessManager, () => const LocalProcessManager());
     testContext.putIfAbsent(Logger, () => new BufferLogger());
     testContext.putIfAbsent(Config, () => new Config());