MultiView changes for dart:ui (#42493)

Fixes flutter/flutter#124991.

Framework tests are failing because I need to do a pre-migration of `flutter_test` for the Object -> int change of viewId. That's in flutter/flutter#128092.

Author: goderbauer

lib/ui/fixtures/ui_test.dart

@@ -538,6 +538,37 @@ void hooksTests() async {
     expectEquals(x.countryCode, y.countryCode);
   });
 
+  await test('PlatformDispatcher.view getter returns view with provided ID', () {
+    const int viewId = 123456789;
+    _callHook(
+      '_updateWindowMetrics',
+      21,
+      viewId, // window Id
+      1.0, // devicePixelRatio
+      800.0, // width
+      600.0, // height
+      50.0, // paddingTop
+      0.0, // paddingRight
+      40.0, // paddingBottom
+      0.0, // paddingLeft
+      0.0, // insetTop
+      0.0, // insetRight
+      0.0, // insetBottom
+      0.0, // insetLeft
+      0.0, // systemGestureInsetTop
+      0.0, // systemGestureInsetRight
+      0.0, // systemGestureInsetBottom
+      0.0, // systemGestureInsetLeft
+      22.0, // physicalTouchSlop
+      <double>[],  // display features bounds
+      <int>[],     // display features types
+      <int>[],     // display features states
+      0, // Display ID
+    );
+
+    expectEquals(PlatformDispatcher.instance.view(id: viewId)?.viewId, viewId);
+  });
+
   await test('View padding/insets/viewPadding/systemGestureInsets', () {
     _callHook(
       '_updateWindowMetrics',
@@ -602,7 +633,7 @@ void hooksTests() async {
     expectEquals(window.systemGestureInsets.bottom, 44.0);
   });
 
-   await test('Window physical touch slop', () {
+  await test('Window physical touch slop', () {
     _callHook(
       '_updateWindowMetrics',
       21,
@@ -816,6 +847,25 @@ void hooksTests() async {
     expectEquals(action, 4);
   });
 
+  await test('onSemanticsActionEvent preserves callback zone', () {
+    late Zone innerZone;
+    late Zone runZone;
+    late SemanticsActionEvent action;
+
+    runZoned(() {
+      innerZone = Zone.current;
+      PlatformDispatcher.instance.onSemanticsActionEvent = (SemanticsActionEvent actionEvent) {
+        runZone = Zone.current;
+        action = actionEvent;
+      };
+    });
+
+    _callHook('_dispatchSemanticsAction', 3, 1234, 4, null);
+    expectIdentical(runZone, innerZone);
+    expectEquals(action.nodeId, 1234);
+    expectEquals(action.type.index, 4);
+  });
+
   await test('onPlatformMessage preserves callback zone', () {
     late Zone innerZone;
     late Zone runZone;

lib/ui/hooks.dart

@@ -32,7 +32,7 @@ void _updateDisplays(
 
 @pragma('vm:entry-point')
 void _updateWindowMetrics(
-  Object id,
+  int id,
   double devicePixelRatio,
   double width,
   double height,

lib/ui/platform_dispatcher.dart

@@ -33,8 +33,12 @@ typedef PointerDataPacketCallback = void Function(PointerDataPacket packet);
 typedef KeyDataCallback = bool Function(KeyData data);
 
 /// Signature for [PlatformDispatcher.onSemanticsAction].
+// TODO(goderbauer): Deprecate/remove this when the framework has migrated to SemanticsActionEventCallback.
 typedef SemanticsActionCallback = void Function(int nodeId, SemanticsAction action, ByteData? args);
 
+/// Signature for [PlatformDispatcher.onSemanticsActionEvent].
+typedef SemanticsActionEventCallback = void Function(SemanticsActionEvent action);
+
 /// Signature for responses to platform messages.
 ///
 /// Used as a parameter to [PlatformDispatcher.sendPlatformMessage] and
@@ -174,7 +178,11 @@ class PlatformDispatcher {
   ///
   /// If any of their configurations change, [onMetricsChanged] will be called.
   Iterable<FlutterView> get views => _views.values;
-  final Map<Object, FlutterView> _views = <Object, FlutterView>{};
+  final Map<int, FlutterView> _views = <int, FlutterView>{};
+
+  /// Returns the [FlutterView] with the provided ID if one exists, or null
+  /// otherwise.
+  FlutterView? view({required int id}) => _views[id];
 
   // A map of opaque platform view identifiers to view configurations.
   final Map<Object, _ViewConfiguration> _viewConfigurations = <Object, _ViewConfiguration>{};
@@ -250,7 +258,7 @@ class PlatformDispatcher {
   //
   // Updates the metrics of the window with the given id.
   void _updateWindowMetrics(
-    Object id,
+    int id,
     double devicePixelRatio,
     double width,
     double height,
@@ -436,6 +444,7 @@ class PlatformDispatcher {
     for (int i = 0; i < length; ++i) {
       int offset = i * _kPointerDataFieldCount;
       data.add(PointerData(
+        // TODO(goderbauer): Wire up viewId.
         embedderId: packet.getInt64(kStride * offset++, _kFakeHostEndian),
         timeStamp: Duration(microseconds: packet.getInt64(kStride * offset++, _kFakeHostEndian)),
         change: PointerChange.values[packet.getInt64(kStride * offset++, _kFakeHostEndian)],
@@ -1150,6 +1159,7 @@ class PlatformDispatcher {
   ///
   /// The framework invokes this callback in the same zone in which the
   /// callback was set.
+  // TODO(goderbauer): Deprecate/remove this when the framework has migrated to onSemanticsActionEvent.
   SemanticsActionCallback? get onSemanticsAction => _onSemanticsAction;
   SemanticsActionCallback? _onSemanticsAction;
   Zone _onSemanticsActionZone = Zone.root;
@@ -1158,6 +1168,22 @@ class PlatformDispatcher {
     _onSemanticsActionZone = Zone.current;
   }
 
+  /// A callback that is invoked whenever the user requests an action to be
+  /// performed on a semantics node.
+  ///
+  /// This callback is used when the user expresses the action they wish to
+  /// perform based on the semantics node supplied by updateSemantics.
+  ///
+  /// The framework invokes this callback in the same zone in which the
+  /// callback was set.
+  SemanticsActionEventCallback? get onSemanticsActionEvent => _onSemanticsActionEvent;
+  SemanticsActionEventCallback? _onSemanticsActionEvent;
+  Zone _onSemanticsActionEventZone = Zone.root;
+  set onSemanticsActionEvent(SemanticsActionEventCallback? callback) {
+    _onSemanticsActionEvent = callback;
+    _onSemanticsActionEventZone = Zone.current;
+  }
+
   // Called from the engine via hooks.dart.
   void _updateFrameData(int frameNumber) {
     final FrameData previous = _frameData;
@@ -1190,6 +1216,16 @@ class PlatformDispatcher {
       SemanticsAction.fromIndex(action)!,
       args,
     );
+    _invoke1<SemanticsActionEvent>(
+      onSemanticsActionEvent,
+      _onSemanticsActionEventZone,
+      SemanticsActionEvent(
+        type: SemanticsAction.fromIndex(action)!,
+        nodeId: nodeId,
+        viewId: 0, // TODO(goderbauer): Wire up the real view ID.
+        arguments: args,
+      ),
+    );
   }
 
   ErrorCallback? _onError;
@@ -2350,3 +2386,49 @@ enum DartPerformanceMode {
   /// frequently performing work.
   memory,
 }
+
+/// An event to request a [SemanticsAction] of [type] to be performed on the
+/// [SemanticsNode] identified by [nodeId] owned by the [FlutterView] identified
+/// by [viewId].
+///
+/// Used by [SemanticsBinding.performSemanticsAction].
+class SemanticsActionEvent {
+  /// Creates a [SemanticsActionEvent].
+  const SemanticsActionEvent({
+    required this.type,
+    required this.viewId,
+    required this.nodeId,
+    this.arguments,
+  });
+
+  /// The type of action to be performed.
+  final SemanticsAction type;
+
+  /// The id of the [FlutterView] the [SemanticsNode] identified by [nodeId] is
+  /// associated with.
+  final int viewId;
+
+  /// The id of the [SemanticsNode] on which the action is to be performed.
+  final int nodeId;
+
+  /// Optional arguments for the action.
+  final Object? arguments;
+
+  static const Object _noArgumentPlaceholder = Object();
+
+  /// Create a clone of the [SemanticsActionEvent] but with provided parameters
+  /// replaced.
+  SemanticsActionEvent copyWith({
+    SemanticsAction? type,
+    int? viewId,
+    int? nodeId,
+    Object? arguments = _noArgumentPlaceholder,
+  }) {
+    return SemanticsActionEvent(
+      type: type ?? this.type,
+      viewId: viewId ?? this.viewId,
+      nodeId: nodeId ?? this.nodeId,
+      arguments: arguments == _noArgumentPlaceholder ? this.arguments : arguments,
+    );
+  }
+}

lib/ui/pointer.dart

@@ -141,6 +141,7 @@ enum PointerSignalKind {
 class PointerData {
   /// Creates an object that represents the state of a pointer.
   const PointerData({
+    this.viewId = 0,
     this.embedderId = 0,
     this.timeStamp = Duration.zero,
     this.change = PointerChange.cancel,
@@ -178,11 +179,16 @@ class PointerData {
     this.rotation = 0.0,
   });
 
-  /// Unique identifier that ties the [PointerEvent] to embedder event created it.
+  /// The ID of the [FlutterView] this [PointerEvent] originated from.
+  final int viewId;
+
+  /// Unique identifier that ties the [PointerEvent] to the embedder
+  /// event that created it.
+  /// it.
   ///
-  /// No two pointer events can have the same [embedderId]. This is different from
-  /// [pointerIdentifier] - used for hit-testing, whereas [embedderId] is used to
-  /// identify the platform event.
+  /// No two pointer events can have the same [embedderId]. This is different
+  /// from [pointerIdentifier] - used for hit-testing, whereas [embedderId] is
+  /// used to identify the platform event.
   final int embedderId;
 
   /// Time of event dispatch, relative to an arbitrary timeline.

lib/ui/window.dart

@@ -89,7 +89,7 @@ class FlutterView {
   FlutterView._(this.viewId, this.platformDispatcher);
 
   /// The opaque ID for this view.
-  final Object viewId;
+  final int viewId;
 
   /// The platform dispatcher that this view is registered with, and gets its
   /// information from.

lib/web_ui/lib/platform_dispatcher.dart

@@ -10,6 +10,7 @@ typedef TimingsCallback = void Function(List<FrameTiming> timings);
 typedef PointerDataPacketCallback = void Function(PointerDataPacket packet);
 typedef KeyDataCallback = bool Function(KeyData data);
 typedef SemanticsActionCallback = void Function(int nodeId, SemanticsAction action, ByteData? args);
+typedef SemanticsActionEventCallback = void Function(SemanticsActionEvent action);
 typedef PlatformMessageResponseCallback = void Function(ByteData? data);
 typedef PlatformMessageCallback = void Function(
     String name, ByteData? data, PlatformMessageResponseCallback? callback);
@@ -33,6 +34,8 @@ abstract class PlatformDispatcher {
 
   Iterable<FlutterView> get views;
 
+  FlutterView? view({required int id});
+
   FlutterView? get implicitView;
 
   VoidCallback? get onMetricsChanged;
@@ -135,6 +138,9 @@ abstract class PlatformDispatcher {
   SemanticsActionCallback? get onSemanticsAction;
   set onSemanticsAction(SemanticsActionCallback? callback);
 
+  SemanticsActionEventCallback? get onSemanticsActionEvent;
+  set onSemanticsActionEvent(SemanticsActionEventCallback? callback);
+
   ErrorCallback? get onError;
   set onError(ErrorCallback? callback);
 
@@ -493,3 +499,33 @@ enum DartPerformanceMode {
   throughput,
   memory,
 }
+
+class SemanticsActionEvent {
+  const SemanticsActionEvent({
+    required this.type,
+    required this.viewId,
+    required this.nodeId,
+    this.arguments,
+  });
+
+  final SemanticsAction type;
+  final int viewId;
+  final int nodeId;
+  final Object? arguments;
+
+  static const Object _noArgumentPlaceholder = Object();
+
+  SemanticsActionEvent copyWith({
+    SemanticsAction? type,
+    int? viewId,
+    int? nodeId,
+    Object? arguments = _noArgumentPlaceholder,
+  }) {
+    return SemanticsActionEvent(
+      type: type ?? this.type,
+      viewId: viewId ?? this.viewId,
+      nodeId: nodeId ?? this.nodeId,
+      arguments: arguments == _noArgumentPlaceholder ? this.arguments : arguments,
+    );
+  }
+}

lib/web_ui/lib/pointer.dart

@@ -36,6 +36,7 @@ enum PointerSignalKind {
 
 class PointerData {
   const PointerData({
+    this.viewId = 0,
     this.embedderId = 0,
     this.timeStamp = Duration.zero,
     this.change = PointerChange.cancel,
@@ -72,6 +73,7 @@ class PointerData {
     this.scale = 0.0,
     this.rotation = 0.0,
   });
+  final int viewId;
   final int embedderId;
   final Duration timeStamp;
   final PointerChange change;

lib/web_ui/lib/src/engine/platform_dispatcher.dart

@@ -165,7 +165,12 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
   /// The current list of windows.
   @override
   Iterable<ui.FlutterView> get views => viewData.values;
-  final Map<Object, ui.FlutterView> viewData = <Object, ui.FlutterView>{};
+  final Map<int, ui.FlutterView> viewData = <int, ui.FlutterView>{};
+
+  /// Returns the [FlutterView] with the provided ID if one exists, or null
+  /// otherwise.
+  @override
+  ui.FlutterView? view({required int id}) => viewData[id];
 
   /// A map of opaque platform window identifiers to window configurations.
   ///
@@ -1206,12 +1211,38 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
     _onSemanticsActionZone = Zone.current;
   }
 
+  /// A callback that is invoked whenever the user requests an action to be
+  /// performed on a semantics node.
+  ///
+  /// This callback is used when the user expresses the action they wish to
+  /// perform based on the semantics node supplied by updateSemantics.
+  ///
+  /// The framework invokes this callback in the same zone in which the
+  /// callback was set.
+  @override
+  ui.SemanticsActionEventCallback? get onSemanticsActionEvent => _onSemanticsActionEvent;
+  ui.SemanticsActionEventCallback? _onSemanticsActionEvent;
+  Zone _onSemanticsActionEventZone = Zone.root;
+  @override
+  set onSemanticsActionEvent(ui.SemanticsActionEventCallback? callback) {
+    _onSemanticsActionEvent = callback;
+    _onSemanticsActionEventZone = Zone.current;
+  }
+
   /// Engine code should use this method instead of the callback directly.
   /// Otherwise zones won't work properly.
   void invokeOnSemanticsAction(
       int nodeId, ui.SemanticsAction action, ByteData? args) {
     invoke3<int, ui.SemanticsAction, ByteData?>(
         _onSemanticsAction, _onSemanticsActionZone, nodeId, action, args);
+    invoke1<ui.SemanticsActionEvent>(
+        _onSemanticsActionEvent, _onSemanticsActionEventZone, ui.SemanticsActionEvent(
+          type: action,
+          nodeId: nodeId,
+          viewId: 0, // TODO(goderbauer): Wire up the real view ID.
+          arguments: args,
+        ),
+    );
   }
 
   // TODO(dnfield): make this work on web.

lib/web_ui/lib/src/engine/window.dart

@@ -51,7 +51,7 @@ class EngineFlutterWindow extends ui.SingletonFlutterWindow {
   }
 
   @override
-  final Object viewId;
+  final int viewId;
 
   @override
   final ui.PlatformDispatcher platformDispatcher;