Revert "Migration to PlatformDispatcher and multi-window #20496" (#21792)

* Revert "Fix documentation build for window changes. (#21780)"

This reverts commit 931a0468.

* Revert "Migration to PlatformDispatcher and multi-window (#20496)"

This reverts commit 85b0031f.

ci/licenses_golden/licenses_flutter

@@ -371,7 +371,6 @@ FILE: ../../../flutter/lib/ui/painting/single_frame_codec.h
 FILE: ../../../flutter/lib/ui/painting/vertices.cc
 FILE: ../../../flutter/lib/ui/painting/vertices.h
 FILE: ../../../flutter/lib/ui/painting/vertices_unittests.cc
-FILE: ../../../flutter/lib/ui/platform_dispatcher.dart
 FILE: ../../../flutter/lib/ui/plugins.dart
 FILE: ../../../flutter/lib/ui/plugins/callback_cache.cc
 FILE: ../../../flutter/lib/ui/plugins/callback_cache.h
@@ -500,7 +499,6 @@ FILE: ../../../flutter/lib/web_ui/lib/src/engine/keyboard.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/mouse_cursor.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/onscreen_logging.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/picture.dart
-FILE: ../../../flutter/lib/web_ui/lib/src/engine/platform_dispatcher.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/platform_views.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/plugins.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/pointer_binding.dart
@@ -555,7 +553,6 @@ FILE: ../../../flutter/lib/web_ui/lib/src/ui/natives.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/ui/painting.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/ui/path.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/ui/path_metrics.dart
-FILE: ../../../flutter/lib/web_ui/lib/src/ui/platform_dispatcher.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/ui/pointer.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/ui/semantics.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/ui/test_embedding.dart

lib/ui/compositing.dart

@@ -10,8 +10,8 @@ part of dart.ui;
 ///
 /// To create a Scene object, use a [SceneBuilder].
 ///
-/// Scene objects can be displayed on the screen using the [FlutterView.render]
-/// method.
+/// Scene objects can be displayed on the screen using the
+/// [Window.render] method.
 @pragma('vm:entry-point')
 class Scene extends NativeFieldWrapperClass2 {
   /// This class is created by the engine, and should not be instantiated
@@ -186,7 +186,7 @@ class PhysicalShapeEngineLayer extends _EngineLayerWrapper {
 
 /// Builds a [Scene] containing the given visuals.
 ///
-/// A [Scene] can then be rendered using [FlutterView.render].
+/// A [Scene] can then be rendered using [Window.render].
 ///
 /// To draw graphical operations onto a [Scene], first create a
 /// [Picture] using a [PictureRecorder] and a [Canvas], and then add
@@ -655,13 +655,13 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
   ///  - 0x08: visualizeEngineStatistics - graph UI thread frame times
   /// Set enabledOptions to 0x0F to enable all the currently defined features.
   ///
-  /// The "UI thread" is the thread that includes all the execution of the main
-  /// Dart isolate (the isolate that can call [FlutterView.render]). The UI
-  /// thread frame time is the total time spent executing the
-  /// [PlatformDispatcher.onBeginFrame] callback. The "raster thread" is the
-  /// thread (running on the CPU) that subsequently processes the [Scene]
-  /// provided by the Dart code to turn it into GPU commands and send it to the
-  /// GPU.
+  /// The "UI thread" is the thread that includes all the execution of
+  /// the main Dart isolate (the isolate that can call
+  /// [Window.render]). The UI thread frame time is the total time
+  /// spent executing the [Window.onBeginFrame] callback. The "raster
+  /// thread" is the thread (running on the CPU) that subsequently
+  /// processes the [Scene] provided by the Dart code to turn it into
+  /// GPU commands and send it to the GPU.
   ///
   /// See also the [PerformanceOverlayOption] enum in the rendering library.
   /// for more details.
@@ -802,7 +802,7 @@ class SceneBuilder extends NativeFieldWrapperClass2 {
   ///
   /// Returns a [Scene] containing the objects that have been added to
   /// this scene builder. The [Scene] can then be displayed on the
-  /// screen with [FlutterView.render].
+  /// screen with [Window.render].
   ///
   /// After calling this function, the scene builder object is invalid and
   /// cannot be used further.

lib/ui/compositing/scene.cc

@@ -42,10 +42,9 @@ Scene::Scene(std::shared_ptr<flutter::Layer> rootLayer,
              uint32_t rasterizerTracingThreshold,
              bool checkerboardRasterCacheImages,
              bool checkerboardOffscreenLayers) {
-  // Currently only supports a single window.
   auto viewport_metrics = UIDartState::Current()
                               ->platform_configuration()
-                              ->get_window(0)
+                              ->window()
                               ->viewport_metrics();
 
   layer_tree_ = std::make_unique<LayerTree>(

lib/ui/dart_ui.gni

@@ -13,7 +13,6 @@ dart_ui_files = [
   "//flutter/lib/ui/lerp.dart",
   "//flutter/lib/ui/natives.dart",
   "//flutter/lib/ui/painting.dart",
-  "//flutter/lib/ui/platform_dispatcher.dart",
   "//flutter/lib/ui/plugins.dart",
   "//flutter/lib/ui/pointer.dart",
   "//flutter/lib/ui/semantics.dart",

lib/ui/hooks.dart

@@ -11,7 +11,6 @@ part of dart.ui;
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _updateWindowMetrics(
-  Object id,
   double devicePixelRatio,
   double width,
   double height,
@@ -28,96 +27,186 @@ void _updateWindowMetrics(
   double systemGestureInsetBottom,
   double systemGestureInsetLeft,
 ) {
-  PlatformDispatcher.instance._updateWindowMetrics(
-    id,
-    devicePixelRatio,
-    width,
-    height,
-    viewPaddingTop,
-    viewPaddingRight,
-    viewPaddingBottom,
-    viewPaddingLeft,
-    viewInsetTop,
-    viewInsetRight,
-    viewInsetBottom,
-    viewInsetLeft,
-    systemGestureInsetTop,
-    systemGestureInsetRight,
-    systemGestureInsetBottom,
-    systemGestureInsetLeft,
-  );
+  window
+    .._devicePixelRatio = devicePixelRatio
+    .._physicalSize = Size(width, height)
+    .._viewPadding = WindowPadding._(
+        top: viewPaddingTop,
+        right: viewPaddingRight,
+        bottom: viewPaddingBottom,
+        left: viewPaddingLeft)
+    .._viewInsets = WindowPadding._(
+        top: viewInsetTop,
+        right: viewInsetRight,
+        bottom: viewInsetBottom,
+        left: viewInsetLeft)
+    .._padding = WindowPadding._(
+        top: math.max(0.0, viewPaddingTop - viewInsetTop),
+        right: math.max(0.0, viewPaddingRight - viewInsetRight),
+        bottom: math.max(0.0, viewPaddingBottom - viewInsetBottom),
+        left: math.max(0.0, viewPaddingLeft - viewInsetLeft))
+    .._systemGestureInsets = WindowPadding._(
+        top: math.max(0.0, systemGestureInsetTop),
+        right: math.max(0.0, systemGestureInsetRight),
+        bottom: math.max(0.0, systemGestureInsetBottom),
+        left: math.max(0.0, systemGestureInsetLeft));
+  _invoke(window.onMetricsChanged, window._onMetricsChangedZone);
 }
 
 typedef _LocaleClosure = String? Function();
 
+String? _localeClosure() {
+  if (window.locale == null) {
+    return null;
+  }
+  return window.locale.toString();
+}
+
 @pragma('vm:entry-point')
 // ignore: unused_element
-_LocaleClosure? _getLocaleClosure() => PlatformDispatcher.instance._localeClosure;
+_LocaleClosure? _getLocaleClosure() => _localeClosure;
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _updateLocales(List<String> locales) {
-  PlatformDispatcher.instance._updateLocales(locales);
+  const int stringsPerLocale = 4;
+  final int numLocales = locales.length ~/ stringsPerLocale;
+  final List<Locale> newLocales = <Locale>[];
+  for (int localeIndex = 0; localeIndex < numLocales; localeIndex++) {
+    final String countryCode = locales[localeIndex * stringsPerLocale + 1];
+    final String scriptCode = locales[localeIndex * stringsPerLocale + 2];
+
+    newLocales.add(Locale.fromSubtags(
+      languageCode: locales[localeIndex * stringsPerLocale],
+      countryCode: countryCode.isEmpty ? null : countryCode,
+      scriptCode: scriptCode.isEmpty ? null : scriptCode,
+    ));
+  }
+  window._locales = newLocales;
+  _invoke(window.onLocaleChanged, window._onLocaleChangedZone);
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _updateUserSettingsData(String jsonData) {
-  PlatformDispatcher.instance._updateUserSettingsData(jsonData);
+  final Map<String, dynamic> data = json.decode(jsonData) as Map<String, dynamic>;
+  if (data.isEmpty) {
+    return;
+  }
+  _updateTextScaleFactor((data['textScaleFactor'] as num).toDouble());
+  _updateAlwaysUse24HourFormat(data['alwaysUse24HourFormat'] as bool);
+  _updatePlatformBrightness(data['platformBrightness'] as String);
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _updateLifecycleState(String state) {
-  PlatformDispatcher.instance._updateLifecycleState(state);
+  // We do not update the state if the state has already been used to initialize
+  // the lifecycleState.
+  if (!window._initialLifecycleStateAccessed)
+    window._initialLifecycleState = state;
+}
+
+
+void _updateTextScaleFactor(double textScaleFactor) {
+  window._textScaleFactor = textScaleFactor;
+  _invoke(window.onTextScaleFactorChanged, window._onTextScaleFactorChangedZone);
+}
+
+void _updateAlwaysUse24HourFormat(bool alwaysUse24HourFormat) {
+  window._alwaysUse24HourFormat = alwaysUse24HourFormat;
+}
+
+void _updatePlatformBrightness(String brightnessName) {
+  window._platformBrightness = brightnessName == 'dark' ? Brightness.dark : Brightness.light;
+  _invoke(window.onPlatformBrightnessChanged, window._onPlatformBrightnessChangedZone);
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _updateSemanticsEnabled(bool enabled) {
-  PlatformDispatcher.instance._updateSemanticsEnabled(enabled);
+  window._semanticsEnabled = enabled;
+  _invoke(window.onSemanticsEnabledChanged, window._onSemanticsEnabledChangedZone);
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _updateAccessibilityFeatures(int values) {
-  PlatformDispatcher.instance._updateAccessibilityFeatures(values);
+  final AccessibilityFeatures newFeatures = AccessibilityFeatures._(values);
+  if (newFeatures == window._accessibilityFeatures)
+    return;
+  window._accessibilityFeatures = newFeatures;
+  _invoke(window.onAccessibilityFeaturesChanged, window._onAccessibilityFeaturesChangedZone);
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _dispatchPlatformMessage(String name, ByteData? data, int responseId) {
-  PlatformDispatcher.instance._dispatchPlatformMessage(name, data, responseId);
+  if (name == ChannelBuffers.kControlChannelName) {
+    try {
+      channelBuffers.handleMessage(data!);
+    } catch (ex) {
+      _printDebug('Message to "$name" caused exception $ex');
+    } finally {
+      window._respondToPlatformMessage(responseId, null);
+    }
+  } else if (window.onPlatformMessage != null) {
+    _invoke3<String, ByteData?, PlatformMessageResponseCallback>(
+      window.onPlatformMessage,
+      window._onPlatformMessageZone,
+      name,
+      data,
+      (ByteData? responseData) {
+        window._respondToPlatformMessage(responseId, responseData);
+      },
+    );
+  } else {
+    channelBuffers.push(name, data, (ByteData? responseData) {
+      window._respondToPlatformMessage(responseId, responseData);
+    });
+  }
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _dispatchPointerDataPacket(ByteData packet) {
-  PlatformDispatcher.instance._dispatchPointerDataPacket(packet);
+  if (window.onPointerDataPacket != null)
+    _invoke1<PointerDataPacket>(window.onPointerDataPacket, window._onPointerDataPacketZone, _unpackPointerDataPacket(packet));
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _dispatchSemanticsAction(int id, int action, ByteData? args) {
-  PlatformDispatcher.instance._dispatchSemanticsAction(id, action, args);
+  _invoke3<int, SemanticsAction, ByteData?>(
+    window.onSemanticsAction,
+    window._onSemanticsActionZone,
+    id,
+    SemanticsAction.values[action]!,
+    args,
+  );
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _beginFrame(int microseconds) {
-  PlatformDispatcher.instance._beginFrame(microseconds);
+  _invoke1<Duration>(window.onBeginFrame, window._onBeginFrameZone, Duration(microseconds: microseconds));
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _reportTimings(List<int> timings) {
-  PlatformDispatcher.instance._reportTimings(timings);
+  assert(timings.length % FramePhase.values.length == 0);
+  final List<FrameTiming> frameTimings = <FrameTiming>[];
+  for (int i = 0; i < timings.length; i += FramePhase.values.length) {
+    frameTimings.add(FrameTiming._(timings.sublist(i, i + FramePhase.values.length)));
+  }
+  _invoke1(window.onReportTimings, window._onReportTimingsZone, frameTimings);
 }
 
 @pragma('vm:entry-point')
 // ignore: unused_element
 void _drawFrame() {
-  PlatformDispatcher.instance._drawFrame();
+  _invoke(window.onDrawFrame, window._onDrawFrameZone);
 }
 
 // ignore: always_declare_return_types, prefer_generic_function_type_aliases
@@ -130,7 +219,7 @@ typedef _BinaryFunction(Null args, Null message);
 void _runMainZoned(Function startMainIsolateFunction,
                    Function userMainFunction,
                    List<String> args) {
-  startMainIsolateFunction(() {
+  startMainIsolateFunction((){
     runZonedGuarded<void>(() {
       if (userMainFunction is _BinaryFunction) {
         // This seems to be undocumented but supported by the command line VM.
@@ -150,10 +239,9 @@ void _runMainZoned(Function startMainIsolateFunction,
 void _reportUnhandledException(String error, String stackTrace) native 'PlatformConfiguration_reportUnhandledException';
 
 /// Invokes [callback] inside the given [zone].
-void _invoke(void Function()? callback, Zone zone) {
-  if (callback == null) {
+void _invoke(void callback()?, Zone zone) {
+  if (callback == null)
     return;
-  }
 
   assert(zone != null); // ignore: unnecessary_null_comparison
 
@@ -165,10 +253,9 @@ void _invoke(void Function()? callback, Zone zone) {
 }
 
 /// Invokes [callback] inside the given [zone] passing it [arg].
-void _invoke1<A>(void Function(A a)? callback, Zone zone, A arg) {
-  if (callback == null) {
+void _invoke1<A>(void callback(A a)?, Zone zone, A arg) {
+  if (callback == null)
     return;
-  }
 
   assert(zone != null); // ignore: unnecessary_null_comparison
 
@@ -180,16 +267,9 @@ void _invoke1<A>(void Function(A a)? callback, Zone zone, A arg) {
 }
 
 /// Invokes [callback] inside the given [zone] passing it [arg1], [arg2], and [arg3].
-void _invoke3<A1, A2, A3>(
-  void Function(A1 a1, A2 a2, A3 a3)? callback,
-  Zone zone,
-  A1 arg1,
-  A2 arg2,
-  A3 arg3,
-) {
-  if (callback == null) {
+void _invoke3<A1, A2, A3>(void callback(A1 a1, A2 a2, A3 a3)?, Zone zone, A1 arg1, A2 arg2, A3 arg3) {
+  if (callback == null)
     return;
-  }
 
   assert(zone != null); // ignore: unnecessary_null_comparison
 
@@ -201,3 +281,54 @@ void _invoke3<A1, A2, A3>(
     });
   }
 }
+
+// If this value changes, update the encoding code in the following files:
+//
+//  * pointer_data.cc
+//  * pointer.dart
+//  * AndroidTouchProcessor.java
+const int _kPointerDataFieldCount = 29;
+
+PointerDataPacket _unpackPointerDataPacket(ByteData packet) {
+  const int kStride = Int64List.bytesPerElement;
+  const int kBytesPerPointerData = _kPointerDataFieldCount * kStride;
+  final int length = packet.lengthInBytes ~/ kBytesPerPointerData;
+  assert(length * kBytesPerPointerData == packet.lengthInBytes);
+  final List<PointerData> data = <PointerData>[];
+  for (int i = 0; i < length; ++i) {
+    int offset = i * _kPointerDataFieldCount;
+    data.add(PointerData(
+      embedderId: packet.getInt64(kStride * offset++, _kFakeHostEndian),
+      timeStamp: Duration(microseconds: packet.getInt64(kStride * offset++, _kFakeHostEndian)),
+      change: PointerChange.values[packet.getInt64(kStride * offset++, _kFakeHostEndian)],
+      kind: PointerDeviceKind.values[packet.getInt64(kStride * offset++, _kFakeHostEndian)],
+      signalKind: PointerSignalKind.values[packet.getInt64(kStride * offset++, _kFakeHostEndian)],
+      device: packet.getInt64(kStride * offset++, _kFakeHostEndian),
+      pointerIdentifier: packet.getInt64(kStride * offset++, _kFakeHostEndian),
+      physicalX: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      physicalY: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      physicalDeltaX: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      physicalDeltaY: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      buttons: packet.getInt64(kStride * offset++, _kFakeHostEndian),
+      obscured: packet.getInt64(kStride * offset++, _kFakeHostEndian) != 0,
+      synthesized: packet.getInt64(kStride * offset++, _kFakeHostEndian) != 0,
+      pressure: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      pressureMin: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      pressureMax: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      distance: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      distanceMax: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      size: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      radiusMajor: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      radiusMinor: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      radiusMin: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      radiusMax: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      orientation: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      tilt: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      platformData: packet.getInt64(kStride * offset++, _kFakeHostEndian),
+      scrollDeltaX: packet.getFloat64(kStride * offset++, _kFakeHostEndian),
+      scrollDeltaY: packet.getFloat64(kStride * offset++, _kFakeHostEndian)
+    ));
+    assert(offset == (i + 1) * _kPointerDataFieldCount);
+  }
+  return PointerDataPacket(data: data);
+}

lib/ui/natives.dart

@@ -34,7 +34,7 @@ Future<developer.ServiceExtensionResponse> _scheduleFrame(
     Map<String, String> parameters
     ) async {
   // Schedule the frame.
-  PlatformDispatcher.instance.scheduleFrame();
+  window.scheduleFrame();
   // Always succeed.
   return developer.ServiceExtensionResponse.result(json.encode(<String, String>{
     'type': 'Success',

lib/ui/painting/canvas.cc

@@ -468,7 +468,7 @@ void Canvas::drawShadow(const CanvasPath* path,
   }
   SkScalar dpr = UIDartState::Current()
                      ->platform_configuration()
-                     ->get_window(0)
+                     ->window()
                      ->viewport_metrics()
                      .device_pixel_ratio;
   flutter::PhysicalShapeLayer::DrawShadow(canvas_, path->path(), color,

lib/ui/semantics.dart

@@ -625,8 +625,7 @@ class SemanticsFlag {
 /// An object that creates [SemanticsUpdate] objects.
 ///
 /// Once created, the [SemanticsUpdate] objects can be passed to
-/// [PlatformDispatcher.updateSemantics] to update the semantics conveyed to the
-/// user.
+/// [Window.updateSemantics] to update the semantics conveyed to the user.
 @pragma('vm:entry-point')
 class SemanticsUpdateBuilder extends NativeFieldWrapperClass2 {
   /// Creates an empty [SemanticsUpdateBuilder] object.
@@ -654,10 +653,10 @@ class SemanticsUpdateBuilder extends NativeFieldWrapperClass2 {
   ///
   /// The `actions` are a bit field of [SemanticsAction]s that can be undertaken
   /// by this node. If the user wishes to undertake one of these actions on this
-  /// node, the [PlatformDispatcher.onSemanticsAction] will be called with `id`
-  /// and one of the possible [SemanticsAction]s. Because the semantics tree is
-  /// maintained asynchronously, the [PlatformDispatcher.onSemanticsAction]
-  /// callback might be called with an action that is no longer possible.
+  /// node, the [Window.onSemanticsAction] will be called with `id` and one of
+  /// the possible [SemanticsAction]s. Because the semantics tree is maintained
+  /// asynchronously, the [Window.onSemanticsAction] callback might be called
+  /// with an action that is no longer possible.
   ///
   /// The `label` is a string that describes this node. The `value` property
   /// describes the current value of the node as a string. The `increasedValue`
@@ -833,8 +832,8 @@ class SemanticsUpdateBuilder extends NativeFieldWrapperClass2 {
   /// Creates a [SemanticsUpdate] object that encapsulates the updates recorded
   /// by this object.
   ///
-  /// The returned object can be passed to [PlatformDispatcher.updateSemantics]
-  /// to actually update the semantics retained by the system.
+  /// The returned object can be passed to [Window.updateSemantics] to actually
+  /// update the semantics retained by the system.
   SemanticsUpdate build() {
     final SemanticsUpdate semanticsUpdate = SemanticsUpdate._();
     _build(semanticsUpdate);
@@ -848,7 +847,7 @@ class SemanticsUpdateBuilder extends NativeFieldWrapperClass2 {
 /// To create a SemanticsUpdate object, use a [SemanticsUpdateBuilder].
 ///
 /// Semantics updates can be applied to the system's retained semantics tree
-/// using the [PlatformDispatcher.updateSemantics] method.
+/// using the [Window.updateSemantics] method.
 @pragma('vm:entry-point')
 class SemanticsUpdate extends NativeFieldWrapperClass2 {
   /// This class is created by the engine, and should not be instantiated

lib/ui/text.dart

@@ -2273,7 +2273,7 @@ final ByteData _fontChangeMessage = utf8.encoder.convert(
 ).buffer.asByteData();
 
 FutureOr<void> _sendFontChangeMessage() async {
-  PlatformDispatcher.instance.onPlatformMessage?.call(
+  window.onPlatformMessage?.call(
     'flutter/system',
     _fontChangeMessage,
     (_) {},

lib/ui/ui.dart

@@ -33,7 +33,6 @@ part 'isolate_name_server.dart';
 part 'lerp.dart';
 part 'natives.dart';
 part 'painting.dart';
-part 'platform_dispatcher.dart';
 part 'plugins.dart';
 part 'pointer.dart';
 part 'semantics.dart';

lib/ui/window/platform_configuration.cc

@@ -9,7 +9,6 @@
 #include "flutter/lib/ui/compositing/scene.h"
 #include "flutter/lib/ui/ui_dart_state.h"
 #include "flutter/lib/ui/window/platform_message_response_dart.h"
-#include "flutter/lib/ui/window/viewport_metrics.h"
 #include "flutter/lib/ui/window/window.h"
 #include "third_party/tonic/converter/dart_converter.h"
 #include "third_party/tonic/dart_args.h"
@@ -198,8 +197,7 @@ PlatformConfiguration::~PlatformConfiguration() {}
 void PlatformConfiguration::DidCreateIsolate() {
   library_.Set(tonic::DartState::Current(),
                Dart_LookupLibrary(tonic::ToDart("dart:ui")));
-  windows_.insert(std::make_pair(0, std::unique_ptr<Window>(new Window{
-                                        0, ViewportMetrics{1.0, 0.0, 0.0}})));
+  window_.reset(new Window({1.0, 0.0, 0.0}));
 }
 
 void PlatformConfiguration::UpdateLocales(
@@ -423,7 +421,7 @@ void PlatformConfiguration::RegisterNatives(
        true},
       {"PlatformConfiguration_respondToPlatformMessage",
        _RespondToPlatformMessage, 3, true},
-      {"PlatformConfiguration_render", Render, 3, true},
+      {"PlatformConfiguration_render", Render, 2, true},
       {"PlatformConfiguration_updateSemantics", UpdateSemantics, 2, true},
       {"PlatformConfiguration_setIsolateDebugName", SetIsolateDebugName, 2,
        true},

lib/ui/window/platform_configuration.h

@@ -6,12 +6,14 @@
 #define FLUTTER_LIB_UI_WINDOW_PLATFORM_CONFIGURATION_H_
 
 #include <memory>
+#include <set>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
 #include "flutter/fml/time/time_point.h"
 #include "flutter/lib/ui/semantics/semantics_update.h"
+#include "flutter/lib/ui/window/platform_message.h"
 #include "flutter/lib/ui/window/pointer_data_packet.h"
 #include "flutter/lib/ui/window/viewport_metrics.h"
 #include "flutter/lib/ui/window/window.h"
@@ -376,14 +378,11 @@ class PlatformConfiguration final {
   static void RegisterNatives(tonic::DartLibraryNatives* natives);
 
   //----------------------------------------------------------------------------
-  /// @brief      Retrieves the Window with the given ID managed by the
-  ///             `PlatformConfiguration`.
-  ///
-  /// @param[in] window_id The id of the window to find and return.
+  /// @brief      Retrieves the Window managed by the PlatformConfiguration.
   ///
   /// @return     a pointer to the Window.
   ///
-  Window* get_window(int window_id) { return windows_[window_id].get(); }
+  Window* window() const { return window_.get(); }
 
   //----------------------------------------------------------------------------
   /// @brief      Responds to a previous platform message to the engine from the
@@ -409,7 +408,7 @@ class PlatformConfiguration final {
   PlatformConfigurationClient* client_;
   tonic::DartPersistentValue library_;
 
-  std::unordered_map<int64_t, std::unique_ptr<Window>> windows_;
+  std::unique_ptr<Window> window_;
 
   // We use id 0 to mean that no response is expected.
   int next_response_id_ = 1;

lib/ui/window/platform_configuration_unittests.cc

@@ -54,14 +54,11 @@ TEST_F(ShellTest, PlatformConfigurationInitialization) {
                                          Dart_NativeArguments args) {
     PlatformConfiguration* configuration =
         UIDartState::Current()->platform_configuration();
-    ASSERT_NE(configuration->get_window(0), nullptr);
-    ASSERT_EQ(
-        configuration->get_window(0)->viewport_metrics().device_pixel_ratio,
-        1.0);
-    ASSERT_EQ(configuration->get_window(0)->viewport_metrics().physical_width,
-              0.0);
-    ASSERT_EQ(configuration->get_window(0)->viewport_metrics().physical_height,
-              0.0);
+    ASSERT_NE(configuration->window(), nullptr);
+    ASSERT_EQ(configuration->window()->viewport_metrics().device_pixel_ratio,
+              1.0);
+    ASSERT_EQ(configuration->window()->viewport_metrics().physical_width, 0.0);
+    ASSERT_EQ(configuration->window()->viewport_metrics().physical_height, 0.0);
 
     message_latch->Signal();
   };
@@ -100,15 +97,13 @@ TEST_F(ShellTest, PlatformConfigurationWindowMetricsUpdate) {
     PlatformConfiguration* configuration =
         UIDartState::Current()->platform_configuration();
 
-    ASSERT_NE(configuration->get_window(0), nullptr);
-    configuration->get_window(0)->UpdateWindowMetrics(
+    ASSERT_NE(configuration->window(), nullptr);
+    configuration->window()->UpdateWindowMetrics(
         ViewportMetrics{2.0, 10.0, 20.0});
-    ASSERT_EQ(
-        configuration->get_window(0)->viewport_metrics().device_pixel_ratio,
-        2.0);
-    ASSERT_EQ(configuration->get_window(0)->viewport_metrics().physical_width,
-              10.0);
-    ASSERT_EQ(configuration->get_window(0)->viewport_metrics().physical_height,
+    ASSERT_EQ(configuration->window()->viewport_metrics().device_pixel_ratio,
+              2.0);
+    ASSERT_EQ(configuration->window()->viewport_metrics().physical_width, 10.0);
+    ASSERT_EQ(configuration->window()->viewport_metrics().physical_height,
               20.0);
 
     message_latch->Signal();

lib/ui/window/window.cc

@@ -11,8 +11,7 @@
 
 namespace flutter {
 
-Window::Window(int64_t window_id, ViewportMetrics metrics)
-    : window_id_(window_id), viewport_metrics_(metrics) {
+Window::Window(ViewportMetrics metrics) : viewport_metrics_(metrics) {
   library_.Set(tonic::DartState::Current(),
                Dart_LookupLibrary(tonic::ToDart("dart:ui")));
 }
@@ -47,7 +46,6 @@ void Window::UpdateWindowMetrics(const ViewportMetrics& metrics) {
   tonic::LogIfError(tonic::DartInvokeField(
       library_.value(), "_updateWindowMetrics",
       {
-          tonic::ToDart(window_id_),
           tonic::ToDart(metrics.device_pixel_ratio),
           tonic::ToDart(metrics.physical_width),
           tonic::ToDart(metrics.physical_height),

lib/ui/window/window.h

@@ -18,12 +18,10 @@
 namespace flutter {
 class Window final {
  public:
-  Window(int64_t window_id, ViewportMetrics metrics);
+  explicit Window(ViewportMetrics metrics);
 
   ~Window();
 
-  int window_id() const { return window_id_; }
-
   const ViewportMetrics& viewport_metrics() const { return viewport_metrics_; }
 
   void DispatchPointerDataPacket(const PointerDataPacket& packet);
@@ -31,7 +29,6 @@ class Window final {
 
  private:
   tonic::DartPersistentValue library_;
-  int64_t window_id_;
   ViewportMetrics viewport_metrics_;
 };
 

lib/web_ui/lib/src/engine.dart

@@ -99,7 +99,6 @@ part 'engine/keyboard.dart';
 part 'engine/mouse_cursor.dart';
 part 'engine/onscreen_logging.dart';
 part 'engine/picture.dart';
-part 'engine/platform_dispatcher.dart';
 part 'engine/platform_views.dart';
 part 'engine/plugins.dart';
 part 'engine/pointer_binding.dart';
@@ -225,17 +224,17 @@ void initializeEngine() {
         // part of the rasterization process, particularly in the HTML
         // renderer, takes place in the `SceneBuilder.build()`.
         _frameTimingsOnBuildStart();
-        if (EnginePlatformDispatcher.instance._onBeginFrame != null) {
-          EnginePlatformDispatcher.instance.invokeOnBeginFrame(
+        if (window._onBeginFrame != null) {
+          window.invokeOnBeginFrame(
               Duration(microseconds: highResTimeMicroseconds));
         }
 
-        if (EnginePlatformDispatcher.instance._onDrawFrame != null) {
+        if (window._onDrawFrame != null) {
           // TODO(yjbanov): technically Flutter flushes microtasks between
           //                onBeginFrame and onDrawFrame. We don't, which hasn't
           //                been an issue yet, but eventually we'll have to
           //                implement it properly.
-          EnginePlatformDispatcher.instance.invokeOnDrawFrame();
+          window.invokeOnDrawFrame();
         }
       });
     }

lib/web_ui/lib/src/engine/bitmap_canvas.dart

@@ -71,7 +71,7 @@ class BitmapCanvas extends EngineCanvas {
 
   /// Keeps track of what device pixel ratio was used when this [BitmapCanvas]
   /// was created.
-  final double _devicePixelRatio = EnginePlatformDispatcher.browserDevicePixelRatio;
+  final double _devicePixelRatio = EngineWindow.browserDevicePixelRatio;
 
   // Compensation for [_initializeViewport] snapping canvas position to 1 pixel.
   int? _canvasPositionX, _canvasPositionY;
@@ -150,13 +150,13 @@ class BitmapCanvas extends EngineCanvas {
 
   static int _widthToPhysical(double width) {
     final double boundsWidth = width + 1;
-    return (boundsWidth * EnginePlatformDispatcher.browserDevicePixelRatio).ceil() +
+    return (boundsWidth * EngineWindow.browserDevicePixelRatio).ceil() +
         2 * kPaddingPixels;
   }
 
   static int _heightToPhysical(double height) {
     final double boundsHeight = height + 1;
-    return (boundsHeight * EnginePlatformDispatcher.browserDevicePixelRatio).ceil() +
+    return (boundsHeight * EngineWindow.browserDevicePixelRatio).ceil() +
         2 * kPaddingPixels;
   }
 
@@ -198,7 +198,7 @@ class BitmapCanvas extends EngineCanvas {
   /// * [PersistedPicture._recycleCanvas] which also uses this method
   ///   for the same reason.
   bool isReusable() {
-    return _devicePixelRatio == EnginePlatformDispatcher.browserDevicePixelRatio;
+    return _devicePixelRatio == EngineWindow.browserDevicePixelRatio;
   }
 
   /// Returns a "data://" URI containing a representation of the image in this

lib/web_ui/lib/src/engine/canvas_pool.dart

@@ -99,9 +99,9 @@ class _CanvasPool extends _SaveStackTracking {
       // * To make sure that when we scale the canvas by devicePixelRatio (see
       //   _initializeViewport below) the pixels line up.
       final double cssWidth =
-          _widthInBitmapPixels / EnginePlatformDispatcher.browserDevicePixelRatio;
+          _widthInBitmapPixels / EngineWindow.browserDevicePixelRatio;
       final double cssHeight =
-          _heightInBitmapPixels / EnginePlatformDispatcher.browserDevicePixelRatio;
+          _heightInBitmapPixels / EngineWindow.browserDevicePixelRatio;
       canvas = html.CanvasElement(
         width: _widthInBitmapPixels,
         height: _heightInBitmapPixels,
@@ -194,7 +194,7 @@ class _CanvasPool extends _SaveStackTracking {
             clipTimeTransform[5] != prevTransform[5] ||
             clipTimeTransform[12] != prevTransform[12] ||
             clipTimeTransform[13] != prevTransform[13]) {
-          final double ratio = EnginePlatformDispatcher.browserDevicePixelRatio;
+          final double ratio = EngineWindow.browserDevicePixelRatio;
           ctx.setTransform(ratio, 0, 0, ratio, 0, 0);
           ctx.transform(
               clipTimeTransform[0],
@@ -223,7 +223,7 @@ class _CanvasPool extends _SaveStackTracking {
         transform[5] != prevTransform[5] ||
         transform[12] != prevTransform[12] ||
         transform[13] != prevTransform[13]) {
-      final double ratio = EnginePlatformDispatcher.browserDevicePixelRatio;
+      final double ratio = EngineWindow.browserDevicePixelRatio;
       ctx.setTransform(ratio, 0, 0, ratio, 0, 0);
       ctx.transform(transform[0], transform[1], transform[4], transform[5],
           transform[12], transform[13]);
@@ -307,8 +307,8 @@ class _CanvasPool extends _SaveStackTracking {
 
     // This scale makes sure that 1 CSS pixel is translated to the correct
     // number of bitmap pixels.
-    ctx.scale(EnginePlatformDispatcher.browserDevicePixelRatio,
-        EnginePlatformDispatcher.browserDevicePixelRatio);
+    ctx.scale(EngineWindow.browserDevicePixelRatio,
+        EngineWindow.browserDevicePixelRatio);
   }
 
   void resetTransform() {

lib/web_ui/lib/src/engine/canvaskit/embedded_views.dart

@@ -292,7 +292,7 @@ class HtmlViewEmbedder {
     //
     // HTML elements use logical (CSS) pixels, but we have been using physical
     // pixels, so scale down the head element to match the logical resolution.
-    final double scale = EnginePlatformDispatcher.browserDevicePixelRatio;
+    final double scale = EngineWindow.browserDevicePixelRatio;
     final double inverseScale = 1 / scale;
     final Matrix4 scaleMatrix =
         Matrix4.diagonal3Values(inverseScale, inverseScale, 1);

lib/web_ui/lib/src/engine/canvaskit/skia_object_cache.dart

@@ -348,7 +348,7 @@ class SkiaObjects {
     if (_addedCleanupCallback) {
       return;
     }
-    EnginePlatformDispatcher.instance.rasterizer!.addPostFrameCallback(postFrameCleanUp);
+    window.rasterizer!.addPostFrameCallback(postFrameCleanUp);
     _addedCleanupCallback = true;
   }
 

lib/web_ui/lib/src/engine/dom_renderer.dart

@@ -466,7 +466,7 @@ flt-glass-pane * {
     }
     _localeSubscription = languageChangeEvent.forTarget(html.window)
       .listen(_languageDidChange);
-    EnginePlatformDispatcher.instance._updateLocales();
+    window._updateLocales();
   }
 
   /// Called immediately after browser window metrics change.
@@ -481,18 +481,18 @@ flt-glass-pane * {
   void _metricsDidChange(html.Event? event) {
     if(isMobile && !window.isRotation() && textEditing.isEditing) {
       window.computeOnScreenKeyboardInsets();
-      EnginePlatformDispatcher.instance.invokeOnMetricsChanged();
+      window.invokeOnMetricsChanged();
     } else {
       window._computePhysicalSize();
       // When physical size changes this value has to be recalculated.
       window.computeOnScreenKeyboardInsets();
-      EnginePlatformDispatcher.instance.invokeOnMetricsChanged();
+      window.invokeOnMetricsChanged();
     }
   }
 
   /// Called immediately after browser window language change.
   void _languageDidChange(html.Event event) {
-    EnginePlatformDispatcher.instance._updateLocales();
+    window._updateLocales();
     if (ui.window.onLocaleChanged != null) {
       ui.window.onLocaleChanged!();
     }

lib/web_ui/lib/src/engine/html/render_vertices.dart

@@ -668,8 +668,8 @@ class _OffscreenCanvas {
           height: heightInPixels,
         );
         _glCanvas!.className = 'gl-canvas';
-        final double cssWidth = widthInPixels / EnginePlatformDispatcher.browserDevicePixelRatio;
-        final double cssHeight = heightInPixels / EnginePlatformDispatcher.browserDevicePixelRatio;
+        final double cssWidth = widthInPixels / EngineWindow.browserDevicePixelRatio;
+        final double cssHeight = heightInPixels / EngineWindow.browserDevicePixelRatio;
         _glCanvas!.style
           ..position = 'absolute'
           ..width = '${cssWidth}px'

lib/web_ui/lib/src/engine/html/surface_stats.dart

@@ -125,9 +125,9 @@ void _debugRepaintSurfaceStatsOverlay(PersistedScene scene) {
     ..fill();
 
   final double physicalScreenWidth =
-      html.window.innerWidth! * EnginePlatformDispatcher.browserDevicePixelRatio;
+      html.window.innerWidth! * EngineWindow.browserDevicePixelRatio;
   final double physicalScreenHeight =
-      html.window.innerHeight! * EnginePlatformDispatcher.browserDevicePixelRatio;
+      html.window.innerHeight! * EngineWindow.browserDevicePixelRatio;
   final double physicsScreenPixelCount =
       physicalScreenWidth * physicalScreenHeight;
 
@@ -296,9 +296,9 @@ void _debugPrintSurfaceStats(PersistedScene scene, int frameNumber) {
       return pixels;
     }).fold(0, (int total, int pixels) => total + pixels);
     final double physicalScreenWidth =
-        html.window.innerWidth! * EnginePlatformDispatcher.browserDevicePixelRatio;
+        html.window.innerWidth! * EngineWindow.browserDevicePixelRatio;
     final double physicalScreenHeight =
-        html.window.innerHeight! * EnginePlatformDispatcher.browserDevicePixelRatio;
+        html.window.innerHeight! * EngineWindow.browserDevicePixelRatio;
     final double physicsScreenPixelCount =
         physicalScreenWidth * physicalScreenHeight;
     final double screenPixelRatio = pixelCount / physicsScreenPixelCount;

lib/web_ui/lib/src/engine/keyboard.dart

@@ -81,7 +81,7 @@ class Keyboard {
 
     final html.KeyboardEvent keyboardEvent = event;
 
-    if (EnginePlatformDispatcher.instance._onPlatformMessage == null) {
+    if (window._onPlatformMessage == null) {
       return;
     }
 
@@ -135,7 +135,7 @@ class Keyboard {
       'metaState': _lastMetaState,
     };
 
-    EnginePlatformDispatcher.instance.invokeOnPlatformMessage('flutter/keyevent',
+    window.invokeOnPlatformMessage('flutter/keyevent',
         _messageCodec.encodeMessage(eventData), _noopCallback);
   }
 
@@ -157,7 +157,7 @@ class Keyboard {
       'metaState': _lastMetaState,
     };
 
-    EnginePlatformDispatcher.instance.invokeOnPlatformMessage('flutter/keyevent',
+    window.invokeOnPlatformMessage('flutter/keyevent',
         _messageCodec.encodeMessage(eventData), _noopCallback);
   }
 }

lib/web_ui/lib/src/engine/navigation/history.dart

@@ -151,8 +151,8 @@ class MultiEntriesBrowserHistory extends BrowserHistory {
           currentPath);
     }
     _lastSeenSerialCount = _currentSerialCount;
-    if (EnginePlatformDispatcher.instance._onPlatformMessage != null) {
-      EnginePlatformDispatcher.instance.invokeOnPlatformMessage(
+    if (window._onPlatformMessage != null) {
+      window.invokeOnPlatformMessage(
         'flutter/navigation',
         const JSONMethodCodec().encodeMethodCall(
             MethodCall('pushRouteInformation', <dynamic, dynamic>{
@@ -272,8 +272,8 @@ class SingleEntryBrowserHistory extends BrowserHistory {
       _setupFlutterEntry(urlStrategy!);
 
       // 2. Send a 'popRoute' platform message so the app can handle it accordingly.
-      if (EnginePlatformDispatcher.instance._onPlatformMessage != null) {
-        EnginePlatformDispatcher.instance.invokeOnPlatformMessage(
+      if (window._onPlatformMessage != null) {
+        window.invokeOnPlatformMessage(
           'flutter/navigation',
           const JSONMethodCodec().encodeMethodCall(_popRouteMethodCall),
           (_) {},
@@ -291,8 +291,8 @@ class SingleEntryBrowserHistory extends BrowserHistory {
       _userProvidedRouteName = null;
 
       // Send a 'pushRoute' platform message so the app handles it accordingly.
-      if (EnginePlatformDispatcher.instance._onPlatformMessage != null) {
-        EnginePlatformDispatcher.instance.invokeOnPlatformMessage(
+      if (window._onPlatformMessage != null) {
+        window.invokeOnPlatformMessage(
           'flutter/navigation',
           const JSONMethodCodec().encodeMethodCall(
             MethodCall('pushRoute', newRouteName),

lib/web_ui/lib/src/engine/pointer_binding.dart

@@ -125,7 +125,9 @@ class PointerBinding {
 
   void _onPointerData(Iterable<ui.PointerData> data) {
     final ui.PointerDataPacket packet = ui.PointerDataPacket(data: data.toList());
-    EnginePlatformDispatcher.instance.invokeOnPointerDataPacket(packet);
+    if (window._onPointerDataPacket != null) {
+      window.invokeOnPointerDataPacket(packet);
+    }
   }
 }
 

lib/web_ui/lib/src/engine/profiler.dart

@@ -110,7 +110,7 @@ class Profiler {
 
 /// Whether we are collecting [ui.FrameTiming]s.
 bool get _frameTimingsEnabled {
-  return EnginePlatformDispatcher.instance._onReportTimings != null;
+  return window._onReportTimings != null;
 }
 
 /// Collects frame timings from frames.
@@ -202,7 +202,7 @@ void _frameTimingsOnRasterFinish() {
   _rasterFinishMicros = -1;
   if (now - _frameTimingsLastSubmitTime > _kFrameTimingsSubmitInterval) {
     _frameTimingsLastSubmitTime = now;
-    EnginePlatformDispatcher.instance.invokeOnReportTimings(_frameTimings);
+    window.invokeOnReportTimings(_frameTimings);
     _frameTimings = <ui.FrameTiming>[];
   }
 }

lib/web_ui/lib/src/engine/semantics/incrementable.dart

@@ -53,11 +53,11 @@ class Incrementable extends RoleManager {
       final int newInputValue = int.parse(_element.value!);
       if (newInputValue > _currentSurrogateValue) {
         _currentSurrogateValue += 1;
-        EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
+        window.invokeOnSemanticsAction(
             semanticsObject.id, ui.SemanticsAction.increase, null);
       } else if (newInputValue < _currentSurrogateValue) {
         _currentSurrogateValue -= 1;
-        EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
+        window.invokeOnSemanticsAction(
             semanticsObject.id, ui.SemanticsAction.decrease, null);
       }
     });

lib/web_ui/lib/src/engine/semantics/scrollable.dart

@@ -53,20 +53,20 @@ class Scrollable extends RoleManager {
       final int semanticsId = semanticsObject.id;
       if (doScrollForward) {
         if (semanticsObject.isVerticalScrollContainer) {
-          EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
+          window.invokeOnSemanticsAction(
               semanticsId, ui.SemanticsAction.scrollUp, null);
         } else {
           assert(semanticsObject.isHorizontalScrollContainer);
-          EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
+          window.invokeOnSemanticsAction(
               semanticsId, ui.SemanticsAction.scrollLeft, null);
         }
       } else {
         if (semanticsObject.isVerticalScrollContainer) {
-          EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
+          window.invokeOnSemanticsAction(
               semanticsId, ui.SemanticsAction.scrollDown, null);
         } else {
           assert(semanticsObject.isHorizontalScrollContainer);
-          EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
+          window.invokeOnSemanticsAction(
               semanticsId, ui.SemanticsAction.scrollRight, null);
         }
       }

lib/web_ui/lib/src/engine/semantics/semantics.dart

@@ -1253,8 +1253,8 @@ class EngineSemanticsOwner {
       _gestureModeClock?.datetime = null;
     }
 
-    if (EnginePlatformDispatcher.instance._onSemanticsEnabledChanged != null) {
-      EnginePlatformDispatcher.instance.invokeOnSemanticsEnabledChanged();
+    if (window._onSemanticsEnabledChanged != null) {
+      window.invokeOnSemanticsEnabledChanged();
     }
   }
 

lib/web_ui/lib/src/engine/semantics/tappable.dart

@@ -40,7 +40,7 @@ class Tappable extends RoleManager {
                 GestureMode.browserGestures) {
               return;
             }
-            EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
+            window.invokeOnSemanticsAction(
                 semanticsObject.id, ui.SemanticsAction.tap, null);
           };
           element.addEventListener('click', _clickListener);

lib/web_ui/lib/src/engine/semantics/text_field.dart

@@ -148,7 +148,7 @@ class TextField extends RoleManager {
       }
 
       textEditing.useCustomEditableElement(textEditingElement);
-      EnginePlatformDispatcher.instance
+      window
           .invokeOnSemanticsAction(semanticsObject.id, ui.SemanticsAction.tap, null);
     });
   }
@@ -186,7 +186,7 @@ class TextField extends RoleManager {
 
         if (offsetX * offsetX + offsetY * offsetY < kTouchSlop) {
           // Recognize it as a tap that requires a keyboard.
-          EnginePlatformDispatcher.instance.invokeOnSemanticsAction(
+          window.invokeOnSemanticsAction(
               semanticsObject.id, ui.SemanticsAction.tap, null);
         }
       } else {

lib/web_ui/lib/src/engine/text_editing/text_editing.dart

@@ -276,8 +276,8 @@ class EngineAutofillForm {
 
   /// Sends the 'TextInputClient.updateEditingStateWithTag' message to the framework.
   void _sendAutofillEditingState(String? tag, EditingState editingState) {
-    if (EnginePlatformDispatcher.instance._onPlatformMessage != null) {
-      EnginePlatformDispatcher.instance.invokeOnPlatformMessage(
+    if (window._onPlatformMessage != null) {
+      window.invokeOnPlatformMessage(
         'flutter/textinput',
         const JSONMethodCodec().encodeMethodCall(
           MethodCall(
@@ -1363,7 +1363,7 @@ class TextEditingChannel {
         throw StateError(
             'Unsupported method call on the flutter/textinput channel: ${call.method}');
     }
-    EnginePlatformDispatcher.instance._replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
+    window._replyToPlatformMessage(callback, codec.encodeSuccessEnvelope(true));
   }
 
   /// Used for submitting the forms attached on the DOM.
@@ -1392,8 +1392,8 @@ class TextEditingChannel {
 
   /// Sends the 'TextInputClient.updateEditingState' message to the framework.
   void updateEditingState(int? clientId, EditingState? editingState) {
-    if (EnginePlatformDispatcher.instance._onPlatformMessage != null) {
-      EnginePlatformDispatcher.instance.invokeOnPlatformMessage(
+    if (window._onPlatformMessage != null) {
+      window.invokeOnPlatformMessage(
         'flutter/textinput',
         const JSONMethodCodec().encodeMethodCall(
           MethodCall('TextInputClient.updateEditingState', <dynamic>[
@@ -1408,8 +1408,8 @@ class TextEditingChannel {
 
   /// Sends the 'TextInputClient.performAction' message to the framework.
   void performAction(int? clientId, String? inputAction) {
-    if (EnginePlatformDispatcher.instance._onPlatformMessage != null) {
-      EnginePlatformDispatcher.instance.invokeOnPlatformMessage(
+    if (window._onPlatformMessage != null) {
+      window.invokeOnPlatformMessage(
         'flutter/textinput',
         const JSONMethodCodec().encodeMethodCall(
           MethodCall(
@@ -1424,8 +1424,8 @@ class TextEditingChannel {
 
   /// Sends the 'TextInputClient.onConnectionClosed' message to the framework.
   void onConnectionClosed(int? clientId) {
-    if (EnginePlatformDispatcher.instance._onPlatformMessage != null) {
-      EnginePlatformDispatcher.instance.invokeOnPlatformMessage(
+    if (window._onPlatformMessage != null) {
+      window.invokeOnPlatformMessage(
         'flutter/textinput',
         const JSONMethodCodec().encodeMethodCall(
           MethodCall(

lib/web_ui/lib/src/engine/util.dart

@@ -482,13 +482,13 @@ final ByteData? _fontChangeMessage = JSONMessageCodec().encodeMessage(<String, d
 bool _fontChangeScheduled = false;
 
 FutureOr<void> sendFontChangeMessage() async {
-  if (EnginePlatformDispatcher.instance._onPlatformMessage != null)
+  if (window._onPlatformMessage != null)
     if (!_fontChangeScheduled) {
       _fontChangeScheduled = true;
       // Batch updates into next animationframe.
       html.window.requestAnimationFrame((num _) {
         _fontChangeScheduled = false;
-        EnginePlatformDispatcher.instance.invokeOnPlatformMessage(
+        window.invokeOnPlatformMessage(
           'flutter/system',
           _fontChangeMessage,
               (_) {},

lib/web_ui/lib/src/ui/platform_dispatcher.dart

-// Copyright 2013 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// @dart = 2.10
-part of ui;
-
-typedef VoidCallback = void Function();
-typedef FrameCallback = void Function(Duration duration);
-typedef TimingsCallback = void Function(List<FrameTiming> timings);
-typedef PointerDataPacketCallback = void Function(PointerDataPacket packet);
-typedef SemanticsActionCallback = void Function(int id, SemanticsAction action, ByteData? args);
-typedef PlatformMessageResponseCallback = void Function(ByteData? data);
-typedef PlatformMessageCallback = void Function(
-    String name, ByteData? data, PlatformMessageResponseCallback? callback);
-typedef PlatformConfigurationChangedCallback = void Function(PlatformConfiguration configuration);
-
-abstract class PlatformDispatcher {
-  static PlatformDispatcher get instance => engine.EnginePlatformDispatcher.instance;
-
-  PlatformConfiguration get configuration;
-  VoidCallback? get onPlatformConfigurationChanged;
-  set onPlatformConfigurationChanged(VoidCallback? callback);
-
-  Iterable<FlutterView> get views;
-
-  VoidCallback? get onMetricsChanged;
-  set onMetricsChanged(VoidCallback? callback);
-
-  FrameCallback? get onBeginFrame;
-  set onBeginFrame(FrameCallback? callback);
-
-  VoidCallback? get onDrawFrame;
-  set onDrawFrame(VoidCallback? callback);
-
-  PointerDataPacketCallback? get onPointerDataPacket;
-  set onPointerDataPacket(PointerDataPacketCallback? callback);
-
-  TimingsCallback? get onReportTimings;
-  set onReportTimings(TimingsCallback? callback);
-
-  void sendPlatformMessage(
-      String name,
-      ByteData? data,
-      PlatformMessageResponseCallback? callback,
-  );
-
-  PlatformMessageCallback? get onPlatformMessage;
-  set onPlatformMessage(PlatformMessageCallback? callback);
-
-  void setIsolateDebugName(String name) {}
-
-  ByteData? getPersistentIsolateData() => null;
-
-  void scheduleFrame();
-
-  void render(Scene scene, [FlutterView view]);
-
-  AccessibilityFeatures get accessibilityFeatures;
-
-  VoidCallback? get onAccessibilityFeaturesChanged;
-  set onAccessibilityFeaturesChanged(VoidCallback? callback);
-
-  void updateSemantics(SemanticsUpdate update);
-
-  Locale get locale;
-
-  List<Locale> get locales => configuration.locales;
-
-  Locale? computePlatformResolvedLocale(List<Locale> supportedLocales);
-
-  VoidCallback? get onLocaleChanged;
-  set onLocaleChanged(VoidCallback? callback);
-
-  String get initialLifecycleState => 'AppLifecycleState.resumed';
-
-  bool get alwaysUse24HourFormat => configuration.alwaysUse24HourFormat;
-
-  double get textScaleFactor => configuration.textScaleFactor;
-
-  VoidCallback? get onTextScaleFactorChanged;
-  set onTextScaleFactorChanged(VoidCallback? callback);
-
-  Brightness get platformBrightness => configuration.platformBrightness;
-
-  VoidCallback? get onPlatformBrightnessChanged;
-  set onPlatformBrightnessChanged(VoidCallback? callback);
-
-  bool get semanticsEnabled => configuration.semanticsEnabled;
-
-  VoidCallback? get onSemanticsEnabledChanged;
-  set onSemanticsEnabledChanged(VoidCallback? callback);
-
-  SemanticsActionCallback? get onSemanticsAction;
-  set onSemanticsAction(SemanticsActionCallback? callback);
-
-  String get defaultRouteName;
-}
-
-class PlatformConfiguration {
-  const PlatformConfiguration({
-    this.accessibilityFeatures = const AccessibilityFeatures._(0),
-    this.alwaysUse24HourFormat = false,
-    this.semanticsEnabled = false,
-    this.platformBrightness = Brightness.light,
-    this.textScaleFactor = 1.0,
-    this.locales = const <Locale>[],
-    this.defaultRouteName = '/',
-  });
-
-  PlatformConfiguration copyWith({
-    AccessibilityFeatures? accessibilityFeatures,
-    bool? alwaysUse24HourFormat,
-    bool? semanticsEnabled,
-    Brightness? platformBrightness,
-    double? textScaleFactor,
-    List<Locale>? locales,
-    String? defaultRouteName,
-  }) {
-    return PlatformConfiguration(
-      accessibilityFeatures: accessibilityFeatures ?? this.accessibilityFeatures,
-      alwaysUse24HourFormat: alwaysUse24HourFormat ?? this.alwaysUse24HourFormat,
-      semanticsEnabled: semanticsEnabled ?? this.semanticsEnabled,
-      platformBrightness: platformBrightness ?? this.platformBrightness,
-      textScaleFactor: textScaleFactor ?? this.textScaleFactor,
-      locales: locales ?? this.locales,
-      defaultRouteName: defaultRouteName ?? this.defaultRouteName,
-    );
-  }
-
-  final AccessibilityFeatures accessibilityFeatures;
-  final bool alwaysUse24HourFormat;
-  final bool semanticsEnabled;
-  final Brightness platformBrightness;
-  final double textScaleFactor;
-  final List<Locale> locales;
-  final String defaultRouteName;
-}
-
-class ViewConfiguration {
-  const ViewConfiguration({
-    this.window,
-    this.devicePixelRatio = 1.0,
-    this.geometry = Rect.zero,
-    this.visible = false,
-    this.viewInsets = WindowPadding.zero,
-    this.viewPadding = WindowPadding.zero,
-    this.systemGestureInsets = WindowPadding.zero,
-    this.padding = WindowPadding.zero,
-  });
-
-  ViewConfiguration copyWith({
-    FlutterWindow? window,
-    double? devicePixelRatio,
-    Rect? geometry,
-    bool? visible,
-    WindowPadding? viewInsets,
-    WindowPadding? viewPadding,
-    WindowPadding? systemGestureInsets,
-    WindowPadding? padding,
-  }) {
-    return ViewConfiguration(
-      window: window ?? this.window,
-      devicePixelRatio: devicePixelRatio ?? this.devicePixelRatio,
-      geometry: geometry ?? this.geometry,
-      visible: visible ?? this.visible,
-      viewInsets: viewInsets ?? this.viewInsets,
-      viewPadding: viewPadding ?? this.viewPadding,
-      systemGestureInsets: systemGestureInsets ?? this.systemGestureInsets,
-      padding: padding ?? this.padding,
-    );
-  }
-
-  final FlutterWindow? window;
-  final double devicePixelRatio;
-  final Rect geometry;
-  final bool visible;
-  final WindowPadding viewInsets;
-  final WindowPadding viewPadding;
-  final WindowPadding systemGestureInsets;
-  final WindowPadding padding;
-
-  @override
-  String toString() {
-    return '$runtimeType[window: $window, geometry: $geometry]';
-  }
-}
-
-enum FramePhase {
-  vsyncStart,
-  buildStart,
-  buildFinish,
-  rasterStart,
-  rasterFinish,
-}
-
-class FrameTiming {
-  factory FrameTiming({
-    required int vsyncStart,
-    required int buildStart,
-    required int buildFinish,
-    required int rasterStart,
-    required int rasterFinish,
-  }) {
-    return FrameTiming._(<int>[
-      vsyncStart,
-      buildStart,
-      buildFinish,
-      rasterStart,
-      rasterFinish
-    ]);
-  }
-
-  FrameTiming._(this._timestamps)
-      : assert(_timestamps.length == FramePhase.values.length);
-
-  int timestampInMicroseconds(FramePhase phase) => _timestamps[phase.index];
-
-  Duration _rawDuration(FramePhase phase) => Duration(microseconds: _timestamps[phase.index]);
-
-  Duration get buildDuration =>
-      _rawDuration(FramePhase.buildFinish) - _rawDuration(FramePhase.buildStart);
-
-  Duration get rasterDuration =>
-      _rawDuration(FramePhase.rasterFinish) - _rawDuration(FramePhase.rasterStart);
-
-  Duration get vsyncOverhead => _rawDuration(FramePhase.buildStart) - _rawDuration(FramePhase.vsyncStart);
-
-  Duration get totalSpan =>
-      _rawDuration(FramePhase.rasterFinish) - _rawDuration(FramePhase.vsyncStart);
-
-  final List<int> _timestamps; // in microseconds
-
-  String _formatMS(Duration duration) => '${duration.inMicroseconds * 0.001}ms';
-
-  @override
-  String toString() {
-    return '$runtimeType(buildDuration: ${_formatMS(buildDuration)}, rasterDuration: ${_formatMS(rasterDuration)}, vsyncOverhead: ${_formatMS(vsyncOverhead)}, totalSpan: ${_formatMS(totalSpan)})';
-  }
-}
-
-enum AppLifecycleState {
-  resumed,
-  inactive,
-  paused,
-  detached,
-}
-
-abstract class WindowPadding {
-  const factory WindowPadding._(
-      {required double left,
-      required double top,
-      required double right,
-      required double bottom}) = engine.WindowPadding;
-
-  double get left;
-  double get top;
-  double get right;
-  double get bottom;
-
-  static const WindowPadding zero = WindowPadding._(left: 0.0, top: 0.0, right: 0.0, bottom: 0.0);
-
-  @override
-  String toString() {
-    return 'WindowPadding(left: $left, top: $top, right: $right, bottom: $bottom)';
-  }
-}
-
-class Locale {
-  const Locale(
-    this._languageCode, [
-    this._countryCode,
-  ])  : assert(_languageCode != null), // ignore: unnecessary_null_comparison
-        assert(_languageCode != ''),
-        scriptCode = null;
-
-  const Locale.fromSubtags({
-    String languageCode = 'und',
-    this.scriptCode,
-    String? countryCode,
-  })  : assert(languageCode != null), // ignore: unnecessary_null_comparison
-        assert(languageCode != ''),
-        _languageCode = languageCode,
-        assert(scriptCode != ''),
-        assert(countryCode != ''),
-        _countryCode = countryCode;
-
-  String get languageCode => _deprecatedLanguageSubtagMap[_languageCode] ?? _languageCode;
-  final String _languageCode;
-
-  // This map is generated by //flutter/tools/gen_locale.dart
-  // Mappings generated for language subtag registry as of 2019-02-27.
-  static const Map<String, String> _deprecatedLanguageSubtagMap = <String, String>{
-    'in': 'id', // Indonesian; deprecated 1989-01-01
-    'iw': 'he', // Hebrew; deprecated 1989-01-01
-    'ji': 'yi', // Yiddish; deprecated 1989-01-01
-    'jw': 'jv', // Javanese; deprecated 2001-08-13
-    'mo': 'ro', // Moldavian, Moldovan; deprecated 2008-11-22
-    'aam': 'aas', // Aramanik; deprecated 2015-02-12
-    'adp': 'dz', // Adap; deprecated 2015-02-12
-    'aue': 'ktz', // ǂKxʼauǁʼein; deprecated 2015-02-12
-    'ayx': 'nun', // Ayi (China); deprecated 2011-08-16
-    'bgm': 'bcg', // Baga Mboteni; deprecated 2016-05-30
-    'bjd': 'drl', // Bandjigali; deprecated 2012-08-12
-    'ccq': 'rki', // Chaungtha; deprecated 2012-08-12
-    'cjr': 'mom', // Chorotega; deprecated 2010-03-11
-    'cka': 'cmr', // Khumi Awa Chin; deprecated 2012-08-12
-    'cmk': 'xch', // Chimakum; deprecated 2010-03-11
-    'coy': 'pij', // Coyaima; deprecated 2016-05-30
-    'cqu': 'quh', // Chilean Quechua; deprecated 2016-05-30
-    'drh': 'khk', // Darkhat; deprecated 2010-03-11
-    'drw': 'prs', // Darwazi; deprecated 2010-03-11
-    'gav': 'dev', // Gabutamon; deprecated 2010-03-11
-    'gfx': 'vaj', // Mangetti Dune ǃXung; deprecated 2015-02-12
-    'ggn': 'gvr', // Eastern Gurung; deprecated 2016-05-30
-    'gti': 'nyc', // Gbati-ri; deprecated 2015-02-12
-    'guv': 'duz', // Gey; deprecated 2016-05-30
-    'hrr': 'jal', // Horuru; deprecated 2012-08-12
-    'ibi': 'opa', // Ibilo; deprecated 2012-08-12
-    'ilw': 'gal', // Talur; deprecated 2013-09-10
-    'jeg': 'oyb', // Jeng; deprecated 2017-02-23
-    'kgc': 'tdf', // Kasseng; deprecated 2016-05-30
-    'kgh': 'kml', // Upper Tanudan Kalinga; deprecated 2012-08-12
-    'koj': 'kwv', // Sara Dunjo; deprecated 2015-02-12
-    'krm': 'bmf', // Krim; deprecated 2017-02-23
-    'ktr': 'dtp', // Kota Marudu Tinagas; deprecated 2016-05-30
-    'kvs': 'gdj', // Kunggara; deprecated 2016-05-30
-    'kwq': 'yam', // Kwak; deprecated 2015-02-12
-    'kxe': 'tvd', // Kakihum; deprecated 2015-02-12
-    'kzj': 'dtp', // Coastal Kadazan; deprecated 2016-05-30
-    'kzt': 'dtp', // Tambunan Dusun; deprecated 2016-05-30
-    'lii': 'raq', // Lingkhim; deprecated 2015-02-12
-    'lmm': 'rmx', // Lamam; deprecated 2014-02-28
-    'meg': 'cir', // Mea; deprecated 2013-09-10
-    'mst': 'mry', // Cataelano Mandaya; deprecated 2010-03-11
-    'mwj': 'vaj', // Maligo; deprecated 2015-02-12
-    'myt': 'mry', // Sangab Mandaya; deprecated 2010-03-11
-    'nad': 'xny', // Nijadali; deprecated 2016-05-30
-    'ncp': 'kdz', // Ndaktup; deprecated 2018-03-08
-    'nnx': 'ngv', // Ngong; deprecated 2015-02-12
-    'nts': 'pij', // Natagaimas; deprecated 2016-05-30
-    'oun': 'vaj', // ǃOǃung; deprecated 2015-02-12
-    'pcr': 'adx', // Panang; deprecated 2013-09-10
-    'pmc': 'huw', // Palumata; deprecated 2016-05-30
-    'pmu': 'phr', // Mirpur Panjabi; deprecated 2015-02-12
-    'ppa': 'bfy', // Pao; deprecated 2016-05-30
-    'ppr': 'lcq', // Piru; deprecated 2013-09-10
-    'pry': 'prt', // Pray 3; deprecated 2016-05-30
-    'puz': 'pub', // Purum Naga; deprecated 2014-02-28
-    'sca': 'hle', // Sansu; deprecated 2012-08-12
-    'skk': 'oyb', // Sok; deprecated 2017-02-23
-    'tdu': 'dtp', // Tempasuk Dusun; deprecated 2016-05-30
-    'thc': 'tpo', // Tai Hang Tong; deprecated 2016-05-30
-    'thx': 'oyb', // The; deprecated 2015-02-12
-    'tie': 'ras', // Tingal; deprecated 2011-08-16
-    'tkk': 'twm', // Takpa; deprecated 2011-08-16
-    'tlw': 'weo', // South Wemale; deprecated 2012-08-12
-    'tmp': 'tyj', // Tai Mène; deprecated 2016-05-30
-    'tne': 'kak', // Tinoc Kallahan; deprecated 2016-05-30
-    'tnf': 'prs', // Tangshewi; deprecated 2010-03-11
-    'tsf': 'taj', // Southwestern Tamang; deprecated 2015-02-12
-    'uok': 'ema', // Uokha; deprecated 2015-02-12
-    'xba': 'cax', // Kamba (Brazil); deprecated 2016-05-30
-    'xia': 'acn', // Xiandao; deprecated 2013-09-10
-    'xkh': 'waw', // Karahawyana; deprecated 2016-05-30
-    'xsj': 'suj', // Subi; deprecated 2015-02-12
-    'ybd': 'rki', // Yangbye; deprecated 2012-08-12
-    'yma': 'lrr', // Yamphe; deprecated 2012-08-12
-    'ymt': 'mtm', // Mator-Taygi-Karagas; deprecated 2015-02-12
-    'yos': 'zom', // Yos; deprecated 2013-09-10
-    'yuu': 'yug', // Yugh; deprecated 2014-02-28
-  };
-
-  final String? scriptCode;
-
-  String? get countryCode => _deprecatedRegionSubtagMap[_countryCode] ?? _countryCode;
-  final String? _countryCode;
-
-  // This map is generated by //flutter/tools/gen_locale.dart
-  // Mappings generated for language subtag registry as of 2019-02-27.
-  static const Map<String, String> _deprecatedRegionSubtagMap = <String, String>{
-    'BU': 'MM', // Burma; deprecated 1989-12-05
-    'DD': 'DE', // German Democratic Republic; deprecated 1990-10-30
-    'FX': 'FR', // Metropolitan France; deprecated 1997-07-14
-    'TP': 'TL', // East Timor; deprecated 2002-05-20
-    'YD': 'YE', // Democratic Yemen; deprecated 1990-08-14
-    'ZR': 'CD', // Zaire; deprecated 1997-07-14
-  };
-
-  @override
-  bool operator ==(Object other) {
-    if (identical(this, other)) {
-      return true;
-    }
-    return other is Locale
-        && other.languageCode == languageCode
-        && other.scriptCode == scriptCode
-        && other.countryCode == countryCode;
-  }
-
-  @override
-  int get hashCode => hashValues(languageCode, scriptCode, countryCode);
-
-  @override
-  String toString() => _rawToString('_');
-
-  // TODO(yjbanov): implement to match flutter native.
-  String toLanguageTag() => _rawToString('-');
-
-  String _rawToString(String separator) {
-    final StringBuffer out = StringBuffer(languageCode);
-    if (scriptCode != null) {
-      out.write('$separator$scriptCode');
-    }
-    if (_countryCode != null) {
-      out.write('$separator$countryCode');
-    }
-    return out.toString();
-  }
-}
\ No newline at end of file

lib/web_ui/lib/src/ui/text.dart

 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+// Synced 2019-05-30T14:20:57.833907.
 
 // @dart = 2.10
 part of ui;

lib/web_ui/lib/ui.dart

@@ -29,7 +29,6 @@ part 'src/ui/natives.dart';
 part 'src/ui/painting.dart';
 part 'src/ui/path.dart';
 part 'src/ui/path_metrics.dart';
-part 'src/ui/platform_dispatcher.dart';
 part 'src/ui/pointer.dart';
 part 'src/ui/semantics.dart';
 part 'src/ui/test_embedding.dart';

lib/web_ui/test/canvaskit/skia_objects_cache_test.dart

@@ -50,7 +50,7 @@ void _tests() {
       when(mockRasterizer.addPostFrameCallback(any)).thenAnswer((_) {
         addPostFrameCallbackCount++;
       });
-      EnginePlatformDispatcher.instance.rasterizer = mockRasterizer;
+      window.rasterizer = mockRasterizer;
 
       // Trigger first create
       final TestSkiaObject testObject = TestSkiaObject();

lib/web_ui/test/engine/history_test.dart

@@ -292,7 +292,7 @@ void testMain() {
       expect(strategy.history, hasLength(1));
       expect(strategy.currentEntry.state, _tagStateWithSerialCount('initial state', 0));
       expect(strategy.currentEntry.url, '/home');
-      await routeInformationUpdated('/page1', 'page1 state');
+      await routeInfomrationUpdated('/page1', 'page1 state');
       // Should have two history entries now.
       expect(strategy.history, hasLength(2));
       expect(strategy.currentEntryIndex, 1);
@@ -329,8 +329,8 @@ void testMain() {
       );
       await window.debugInitializeHistory(strategy, useSingle: false);
 
-      await routeInformationUpdated('/page1', 'page1 state');
-      await routeInformationUpdated('/page2', 'page2 state');
+      await routeInfomrationUpdated('/page1', 'page1 state');
+      await routeInfomrationUpdated('/page2', 'page2 state');
 
       // Make sure we are on page2.
       expect(strategy.history, hasLength(3));
@@ -426,8 +426,8 @@ void testMain() {
       );
       await window.debugInitializeHistory(strategy, useSingle: false);
 
-      await routeInformationUpdated('/page1', 'page1 state');
-      await routeInformationUpdated('/page2', 'page2 state');
+      await routeInfomrationUpdated('/page1', 'page1 state');
+      await routeInfomrationUpdated('/page2', 'page2 state');
 
       // Make sure we are on page2.
       expect(strategy.history, hasLength(3));
@@ -522,7 +522,7 @@ Future<void> routeUpdated(String routeName) {
   return completer.future;
 }
 
-Future<void> routeInformationUpdated(String location, dynamic state) {
+Future<void> routeInfomrationUpdated(String location, dynamic state) {
   final Completer<void> completer = Completer<void>();
   window.sendPlatformMessage(
     'flutter/navigation',

lib/web_ui/test/engine/surface/platform_view_test.dart

@@ -15,7 +15,7 @@ import 'package:test/test.dart';
 import '../../matchers.dart';
 
 const MethodCodec codec = StandardMethodCodec();
-final EngineSingletonFlutterWindow window = EngineSingletonFlutterWindow(0, EnginePlatformDispatcher.instance);
+final EngineWindow window = EngineWindow();
 
 void main() {
   internalBootstrapBrowserTest(() => testMain);

lib/web_ui/test/engine/window_test.dart

@@ -31,7 +31,7 @@ void testMain() {
       expect(window.onTextScaleFactorChanged, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnTextScaleFactorChanged();
+    window.invokeOnTextScaleFactorChanged();
   });
 
   test('onPlatformBrightnessChanged preserves the zone', () {
@@ -47,7 +47,7 @@ void testMain() {
       expect(window.onPlatformBrightnessChanged, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnPlatformBrightnessChanged();
+    window.invokeOnPlatformBrightnessChanged();
   });
 
   test('onMetricsChanged preserves the zone', () {
@@ -63,7 +63,7 @@ void testMain() {
       expect(window.onMetricsChanged, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnMetricsChanged();
+    window.invokeOnMetricsChanged();
   });
 
   test('onLocaleChanged preserves the zone', () {
@@ -79,7 +79,7 @@ void testMain() {
       expect(window.onLocaleChanged, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnLocaleChanged();
+    window.invokeOnLocaleChanged();
   });
 
   test('onBeginFrame preserves the zone', () {
@@ -95,7 +95,7 @@ void testMain() {
       expect(window.onBeginFrame, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnBeginFrame(null);
+    window.invokeOnBeginFrame(null);
   });
 
   test('onReportTimings preserves the zone', () {
@@ -111,7 +111,7 @@ void testMain() {
       expect(window.onReportTimings, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnReportTimings(null);
+    window.invokeOnReportTimings(null);
   });
 
   test('onDrawFrame preserves the zone', () {
@@ -127,7 +127,7 @@ void testMain() {
       expect(window.onDrawFrame, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnDrawFrame();
+    window.invokeOnDrawFrame();
   });
 
   test('onPointerDataPacket preserves the zone', () {
@@ -143,7 +143,7 @@ void testMain() {
       expect(window.onPointerDataPacket, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnPointerDataPacket(null);
+    window.invokeOnPointerDataPacket(null);
   });
 
   test('onSemanticsEnabledChanged preserves the zone', () {
@@ -159,7 +159,7 @@ void testMain() {
       expect(window.onSemanticsEnabledChanged, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnSemanticsEnabledChanged();
+    window.invokeOnSemanticsEnabledChanged();
   });
 
   test('onSemanticsAction preserves the zone', () {
@@ -175,7 +175,7 @@ void testMain() {
       expect(window.onSemanticsAction, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnSemanticsAction(null, null, null);
+    window.invokeOnSemanticsAction(null, null, null);
   });
 
   test('onAccessibilityFeaturesChanged preserves the zone', () {
@@ -191,7 +191,7 @@ void testMain() {
       expect(window.onAccessibilityFeaturesChanged, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnAccessibilityFeaturesChanged();
+    window.invokeOnAccessibilityFeaturesChanged();
   });
 
   test('onPlatformMessage preserves the zone', () {
@@ -207,7 +207,7 @@ void testMain() {
       expect(window.onPlatformMessage, same(callback));
     });
 
-    EnginePlatformDispatcher.instance.invokeOnPlatformMessage(null, null, null);
+    window.invokeOnPlatformMessage(null, null, null);
   });
 
   test('sendPlatformMessage preserves the zone', () async {
@@ -290,8 +290,8 @@ void testMain() {
     // Trigger a change notification (reset locales because the notification
     // doesn't actually change the list of languages; the test only observes
     // that the list is populated again).
-    EnginePlatformDispatcher.instance.debugResetLocales();
-    expect(window.locales, isEmpty);
+    window.debugResetLocales();
+    expect(window.locales, null);
     expect(localeChangedCount, 0);
     html.window.dispatchEvent(html.Event('languagechange'));
     expect(window.locales, isNotEmpty);

lib/web_ui/test/golden_tests/engine/canvas_golden_test.dart

@@ -227,8 +227,8 @@ void testMain() async {
     );
 
     final SceneBuilder sb = SceneBuilder();
-    sb.pushTransform(Matrix4.diagonal3Values(EnginePlatformDispatcher.browserDevicePixelRatio,
-        EnginePlatformDispatcher.browserDevicePixelRatio, 1.0).toFloat64());
+    sb.pushTransform(Matrix4.diagonal3Values(EngineWindow.browserDevicePixelRatio,
+        EngineWindow.browserDevicePixelRatio, 1.0).toFloat64());
     sb.pushTransform(Matrix4.rotationZ(math.pi / 2).toFloat64());
     sb.pushOffset(0, -500);
     sb.pushClipRect(canvasSize);

lib/web_ui/test/golden_tests/engine/compositing_golden_test.dart

@@ -412,8 +412,8 @@ void _testCullRectComputation() {
     final SurfaceSceneBuilder builder = SurfaceSceneBuilder();
 
     builder.pushTransform(Matrix4.diagonal3Values(
-        EnginePlatformDispatcher.browserDevicePixelRatio,
-        EnginePlatformDispatcher.browserDevicePixelRatio, 1.0).toFloat64());
+        EngineWindow.browserDevicePixelRatio,
+        EngineWindow.browserDevicePixelRatio, 1.0).toFloat64());
 
     // TODO(yjbanov): see the TODO below.
     // final double screenWidth = html.window.innerWidth.toDouble();

lib/web_ui/test/window_test.dart

@@ -71,7 +71,7 @@ void testMain() {
     expect(window.browserHistory.currentPath, '/');
 
     // Perform some navigation operations.
-    routeInformationUpdated('/foo/bar', null);
+    routeInfomrationUpdated('/foo/bar', null);
     // Path should not be updated because URL strategy is disabled.
     expect(window.browserHistory.currentPath, '/');
   });

runtime/runtime_controller.cc

@@ -188,7 +188,7 @@ bool RuntimeController::SetViewportMetrics(const ViewportMetrics& metrics) {
   platform_data_.viewport_metrics = metrics;
 
   if (auto* platform_configuration = GetPlatformConfigurationIfAvailable()) {
-    platform_configuration->get_window(0)->UpdateWindowMetrics(metrics);
+    platform_configuration->window()->UpdateWindowMetrics(metrics);
     return true;
   }
 
@@ -310,7 +310,7 @@ bool RuntimeController::DispatchPointerDataPacket(
   if (auto* platform_configuration = GetPlatformConfigurationIfAvailable()) {
     TRACE_EVENT1("flutter", "RuntimeController::DispatchPointerDataPacket",
                  "mode", "basic");
-    platform_configuration->get_window(0)->DispatchPointerDataPacket(packet);
+    platform_configuration->window()->DispatchPointerDataPacket(packet);
     return true;
   }
 

runtime/runtime_controller.h

@@ -147,7 +147,7 @@ class RuntimeController : public PlatformConfigurationClient {
   ///             If the isolate is not running, these metrics will be saved and
   ///             flushed to the isolate when it starts.
   ///
-  /// @param[in]  metrics  The window's viewport metrics.
+  /// @param[in]  metrics  The viewport metrics.
   ///
   /// @return     If the window metrics were forwarded to the running isolate.
   ///

shell/common/engine.h

@@ -202,14 +202,13 @@ class Engine final : public RuntimeDelegate,
     /// @brief      Notifies the shell of the name of the root isolate and its
     ///             port when that isolate is launched, restarted (in the
     ///             cold-restart scenario) or the application itself updates the
-    ///             name of the root isolate (via
-    ///             `PlatformDispatcher.setIsolateDebugName` in
-    ///             `platform_dispatcher.dart`). The name of the isolate is
-    ///             meaningless to the engine but is used in instrumentation and
-    ///             tooling. Currently, this information is to update the
-    ///             service protocol list of available root isolates running in
-    ///             the VM and their names so that the appropriate isolate can
-    ///             be selected in the tools for debugging and instrumentation.
+    ///             name of the root isolate (via `Window.setIsolateDebugName`
+    ///             in `window.dart`). The name of the isolate is meaningless to
+    ///             the engine but is used in instrumentation and tooling.
+    ///             Currently, this information is to update the service
+    ///             protocol list of available root isolates running in the VM
+    ///             and their names so that the appropriate isolate can be
+    ///             selected in the tools for debugging and instrumentation.
     ///
     /// @param[in]  isolate_name  The isolate name
     /// @param[in]  isolate_port  The isolate port
@@ -553,8 +552,8 @@ class Engine final : public RuntimeDelegate,
   ///             "main.dart", the entrypoint is "main" and the port name
   ///             "1234". Once launched, the isolate may re-christen itself
   ///             using a name it selects via `setIsolateDebugName` in
-  ///             `platform_dispatcher.dart`. This name is purely advisory and
-  ///             only used by instrumentation and reporting purposes.
+  ///             `window.dart`. This name is purely advisory and only used by
+  ///             instrumentation and reporting purposes.
   ///
   /// @return     The debug name of the root isolate.
   ///