unnecessary this in field initializers (#22522)

dev/devicelab/lib/framework/framework.dart

@@ -148,8 +148,8 @@ class _TaskRunner {
 class TaskResult {
   /// Constructs a successful result.
   TaskResult.success(this.data, {this.benchmarkScoreKeys = const <String>[]})
-      : this.succeeded = true,
-        this.message = 'success' {
+      : succeeded = true,
+        message = 'success' {
     const JsonEncoder prettyJson = JsonEncoder.withIndent('  ');
     if (benchmarkScoreKeys != null) {
       for (String key in benchmarkScoreKeys) {
@@ -173,9 +173,9 @@ class TaskResult {
 
   /// Constructs an unsuccessful result.
   TaskResult.failure(this.message)
-      : this.succeeded = false,
-        this.data = null,
-        this.benchmarkScoreKeys = const <String>[];
+      : succeeded = false,
+        data = null,
+        benchmarkScoreKeys = const <String>[];
 
   /// Whether the task succeeded.
   final bool succeeded;

dev/tools/vitool/lib/vitool.dart

@@ -446,7 +446,7 @@ class _Transform {
 
   /// Constructs a new _Transform, default arguments create a no-op transform.
   _Transform({Matrix3 transformMatrix, this.opacity = 1.0}) :
-      this.transformMatrix = transformMatrix ?? Matrix3.identity();
+      transformMatrix = transformMatrix ?? Matrix3.identity();
 
   final Matrix3 transformMatrix;
   final double opacity;

packages/flutter/lib/src/cupertino/date_picker.dart

@@ -172,7 +172,7 @@ class CupertinoDatePicker extends StatefulWidget {
     this.maximumYear,
     this.minuteInterval = 1,
     this.use24hFormat = false,
-  }) : this.initialDateTime = initialDateTime ?? DateTime.now(),
+  }) : initialDateTime = initialDateTime ?? DateTime.now(),
        assert(mode != null),
        assert(onDateTimeChanged != null),
        assert(initialDateTime != null),

packages/flutter/lib/src/material/button.dart

@@ -49,7 +49,7 @@ class RawMaterialButton extends StatefulWidget {
     this.clipBehavior = Clip.none,
     MaterialTapTargetSize materialTapTargetSize,
     this.child,
-  }) : this.materialTapTargetSize = materialTapTargetSize ?? MaterialTapTargetSize.padded,
+  }) : materialTapTargetSize = materialTapTargetSize ?? MaterialTapTargetSize.padded,
        assert(shape != null),
        assert(elevation != null),
        assert(highlightElevation != null),

packages/flutter/lib/src/material/expansion_panel.dart

@@ -128,7 +128,7 @@ class ExpansionPanelList extends StatefulWidget {
   }) : assert(children != null),
        assert(animationDuration != null),
        _allowOnlyOnePanelOpen = false,
-       this.initialOpenPanelValue = null,
+       initialOpenPanelValue = null,
        super(key: key);
 
   /// Creates a radio expansion panel list widget.

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

@@ -27,7 +27,7 @@ class BottomNavigationBarItem {
     @required this.title,
     Widget activeIcon,
     this.backgroundColor,
-  }) : this.activeIcon = activeIcon ?? icon,
+  }) : activeIcon = activeIcon ?? icon,
        assert(icon != null),
        assert(title != null);
 

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

@@ -78,7 +78,7 @@ abstract class Route<T> {
   ///
   /// If the [settings] are not provided, an empty [RouteSettings] object is
   /// used instead.
-  Route({ RouteSettings settings }) : this.settings = settings ?? const RouteSettings();
+  Route({ RouteSettings settings }) : settings = settings ?? const RouteSettings();
 
   /// The navigator that the route is in, if any.
   NavigatorState get navigator => _navigator;

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

@@ -191,8 +191,8 @@ class ByText extends SerializableFinder {
 class ByValueKey extends SerializableFinder {
   /// Creates a finder given the key value.
   ByValueKey(this.keyValue)
-    : this.keyValueString = '$keyValue',
-      this.keyValueType = '${keyValue.runtimeType}' {
+    : keyValueString = '$keyValue',
+      keyValueType = '${keyValue.runtimeType}' {
     if (!_supportedKeyValueTypes.contains(keyValue.runtimeType))
       throw _createInvalidKeyValueTypeError('$keyValue.runtimeType');
   }

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

@@ -11,7 +11,7 @@ class SetFrameSync extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   SetFrameSync.deserialize(Map<String, String> params)
-      : this.enabled = params['enabled'].toLowerCase() == 'true',
+      : enabled = params['enabled'].toLowerCase() == 'true',
         super.deserialize(params);
 
   /// Whether frameSync should be enabled or disabled.

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

@@ -44,10 +44,10 @@ class Scroll extends CommandWithTarget {
 
   /// Deserializes this command from the value generated by [serialize].
   Scroll.deserialize(Map<String, String> json)
-      : this.dx = double.parse(json['dx']),
-        this.dy = double.parse(json['dy']),
-        this.duration = Duration(microseconds: int.parse(json['duration'])),
-        this.frequency = int.parse(json['frequency']),
+      : dx = double.parse(json['dx']),
+        dy = double.parse(json['dy']),
+        duration = Duration(microseconds: int.parse(json['duration'])),
+        frequency = int.parse(json['frequency']),
         super.deserialize(json);
 
   /// Delta X offset per move event.
@@ -94,7 +94,7 @@ class ScrollIntoView extends CommandWithTarget {
 
   /// Deserializes this command from the value generated by [serialize].
   ScrollIntoView.deserialize(Map<String, String> json)
-      : this.alignment = double.parse(json['alignment']),
+      : alignment = double.parse(json['alignment']),
         super.deserialize(json);
 
   /// How the widget should be aligned.

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

@@ -10,7 +10,7 @@ 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 })
-      : this.timeout = timeout ?? const Duration(seconds: 5);
+      : timeout = timeout ?? const Duration(seconds: 5);
 
   /// Deserializes this command from the value generated by [serialize].
   Command.deserialize(Map<String, String> json)

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

@@ -12,7 +12,7 @@ class RequestData extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   RequestData.deserialize(Map<String, String> params)
-      : this.message = params['message'],
+      : message = params['message'],
         super.deserialize(params);
 
   /// The message being sent from the test to the application.

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

@@ -11,7 +11,7 @@ class SetSemantics extends Command {
 
   /// Deserializes this command from the value generated by [serialize].
   SetSemantics.deserialize(Map<String, String> params)
-      : this.enabled = params['enabled'].toLowerCase() == 'true',
+      : enabled = params['enabled'].toLowerCase() == 'true',
         super.deserialize(params);
 
   /// Whether semantics should be enabled (true) or disabled (false).

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

@@ -207,7 +207,7 @@ class TimelineSummary {
 class TimedEvent {
   /// Creates a timed event given begin and end timestamps in microseconds.
   TimedEvent(int beginTimeMicros, int endTimeMicros)
-    : this.duration = Duration(microseconds: endTimeMicros - beginTimeMicros);
+    : duration = Duration(microseconds: endTimeMicros - beginTimeMicros);
 
   /// The duration of the event.
   final Duration duration;

packages/flutter_localizations/lib/src/material_localizations.dart

@@ -100,19 +100,19 @@ abstract class GlobalMaterialLocalizations implements MaterialLocalizations {
     @required intl.NumberFormat decimalFormat,
     @required intl.NumberFormat twoDigitZeroPaddedFormat,
   }) : assert(localeName != null),
-       this._localeName = localeName,
+       _localeName = localeName,
        assert(fullYearFormat != null),
-       this._fullYearFormat = fullYearFormat,
+       _fullYearFormat = fullYearFormat,
        assert(mediumDateFormat != null),
-       this._mediumDateFormat = mediumDateFormat,
+       _mediumDateFormat = mediumDateFormat,
        assert(longDateFormat != null),
-       this._longDateFormat = longDateFormat,
+       _longDateFormat = longDateFormat,
        assert(yearMonthFormat != null),
-       this._yearMonthFormat = yearMonthFormat,
+       _yearMonthFormat = yearMonthFormat,
        assert(decimalFormat != null),
-       this._decimalFormat = decimalFormat,
+       _decimalFormat = decimalFormat,
        assert(twoDigitZeroPaddedFormat != null),
-       this._twoDigitZeroPaddedFormat = twoDigitZeroPaddedFormat;
+       _twoDigitZeroPaddedFormat = twoDigitZeroPaddedFormat;
 
   final String _localeName;
   final intl.DateFormat _fullYearFormat;

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

@@ -32,7 +32,7 @@ String get javaPath => androidStudio?.javaPath;
 class AndroidStudio implements Comparable<AndroidStudio> {
   AndroidStudio(this.directory,
       {Version version, this.configured, this.studioAppName = 'AndroidStudio'})
-      : this.version = version ?? Version.unknown {
+      : version = version ?? Version.unknown {
     _init();
   }
 

packages/flutter_tools/lib/src/resident_runner.dart

@@ -35,7 +35,7 @@ class FlutterDevice {
     this.fileSystemRoots,
     this.fileSystemScheme,
     ResidentCompiler generator,
-  }) : this.generator = generator ?? ResidentCompiler(
+  }) : generator = generator ?? ResidentCompiler(
          artifacts.getArtifactPath(Artifact.flutterPatchedSdkPath),
          trackWidgetCreation: trackWidgetCreation,
          fileSystemRoots: fileSystemRoots, fileSystemScheme: fileSystemScheme

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

@@ -9,7 +9,7 @@ import 'watcher.dart';
 
 /// Prints JSON events when running a test in --machine mode.
 class EventPrinter extends TestWatcher {
-  EventPrinter({StringSink out}) : this._out = out == null ? stdout: out;
+  EventPrinter({StringSink out}) : _out = out == null ? stdout: out;
 
   final StringSink _out;
 

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

@@ -14,7 +14,7 @@ const bool _includeInsiders = false;
 
 class VsCode {
   VsCode._(this.directory, this.extensionDirectory, { Version version, this.edition })
-      : this.version = version ?? Version.unknown {
+      : version = version ?? Version.unknown {
 
     if (!fs.isDirectorySync(directory)) {
       _validationMessages.add('VS Code not found at $directory');
@@ -195,7 +195,7 @@ class VsCode {
 
 class _VsCodeInstallLocation {
   const _VsCodeInstallLocation(this.installPath, this.extensionsFolder, { this.edition, bool isInsiders })
-    : this.isInsiders = isInsiders ?? false;
+    : isInsiders = isInsiders ?? false;
   final String installPath;
   final String extensionsFolder;
   final String edition;

packages/flutter_tools/test/integration/test_driver.dart

@@ -24,7 +24,7 @@ const Duration quitTimeout = Duration(seconds: 10);
 
 class FlutterTestDriver {
   FlutterTestDriver(this._projectFolder, {String logPrefix}):
-    this._logPrefix = logPrefix != null ? '$logPrefix: ' : '';
+    _logPrefix = logPrefix != null ? '$logPrefix: ' : '';
 
   final Directory _projectFolder;
   final String _logPrefix;

packages/fuchsia_remote_debug_protocol/lib/src/common/logging.dart

@@ -69,9 +69,9 @@ class LogMessage {
   ///
   /// When this message is created, it sets its [time] to [DateTime.now].
   LogMessage(this.message, this.tag, this.level)
-      : this.levelName =
+      : levelName =
             level.toString().substring(level.toString().indexOf('.') + 1),
-        this.time = DateTime.now();
+        time = DateTime.now();
 
   /// The actual log message.
   final String message;