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

@@ -77,9 +77,9 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
     HighContrastSupport.instance.addListener(_updateHighContrast);
     _addFontSizeObserver();
     _addLocaleChangedListener();
-    _addViewFocusChangeListener();
     registerHotRestartListener(dispose);
     AppLifecycleState.instance.addListener(_setAppLifecycleState);
+    _viewFocusBinding.init();
     domDocument.body?.append(accessibilityPlaceholder);
     _onViewDisposedListener = viewManager.onViewDisposed.listen((_) {
       // Send a metrics changed event to the framework when a view is disposed.
@@ -121,7 +121,6 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
     _removeBrightnessMediaQueryListener();
     _disconnectFontSizeObserver();
     _removeLocaleChangedListener();
-    _removeViewFocusChangeListener();
     HighContrastSupport.instance.removeListener(_updateHighContrast);
     AppLifecycleState.instance.removeListener(_setAppLifecycleState);
     _viewFocusBinding.dispose();
@@ -229,17 +228,8 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
     }
   }
 
-  late final ViewFocusBinding _viewFocusBinding = ViewFocusBinding(viewManager);
-  StreamSubscription<ui.ViewFocusEvent>? _onViewFocusChangeSubscription;
-
-  void _addViewFocusChangeListener() {
-    _onViewFocusChangeSubscription = _viewFocusBinding.onViewFocusChange.listen(
-      invokeOnViewFocusChange,
-    );
-  }
-  void _removeViewFocusChangeListener() {
-    _onViewFocusChangeSubscription?.cancel();
-  }
+  late final ViewFocusBinding _viewFocusBinding = 
+    ViewFocusBinding(viewManager, invokeOnViewFocusChange);
 
   @override
   ui.ViewFocusChangeCallback? get onViewFocusChange => _onViewFocusChange;
@@ -261,7 +251,6 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
     );
   }
 
-
   @override
   void requestViewFocusChange({
     required int viewId,
@@ -271,7 +260,6 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
     // TODO(tugorez): implement this method. At the moment will be a no op call.
   }
 
-
   /// A set of views which have rendered in the current `onBeginFrame` or
   /// `onDrawFrame` scope.
   Set<ui.FlutterView>? _viewsRenderedInCurrentFrame;

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

@@ -9,22 +9,17 @@ import 'package:ui/ui.dart' as ui;
 /// Tracks the [FlutterView]s focus changes.
 final class ViewFocusBinding {
   /// Creates a [ViewFocusBinding] instance.
-  ViewFocusBinding(this._viewManager) {
-    _init();
-  }
+  ViewFocusBinding(this._viewManager, this._onViewFocusChange);
 
   final FlutterViewManager _viewManager;
-
-  Stream<ui.ViewFocusEvent> get onViewFocusChange => _onViewFocusChangeController.stream;
-  final StreamController<ui.ViewFocusEvent> _onViewFocusChangeController =
-      StreamController<ui.ViewFocusEvent>.broadcast(sync: true);
-
-  StreamSubscription<int>? _onViewCreatedListener;
+  final ui.ViewFocusChangeCallback _onViewFocusChange;
 
   int? _lastViewId;
   ui.ViewFocusDirection _viewFocusDirection = ui.ViewFocusDirection.forward;
 
-  void _init() {
+  StreamSubscription<int>? _onViewCreatedListener;
+
+  void init() {
     domDocument.body?.addEventListener(_keyDown, _handleKeyDown);
     domDocument.body?.addEventListener(_keyUp, _handleKeyUp);
     domDocument.body?.addEventListener(_focusin, _handleFocusin);
@@ -84,7 +79,7 @@ final class ViewFocusBinding {
     _markViewAsFocusable(_lastViewId, reachableByKeyboard: true);
     _markViewAsFocusable(viewId, reachableByKeyboard: false);
     _lastViewId = viewId;
-    _onViewFocusChangeController.add(event);
+    _onViewFocusChange(event);
   }
 
   int? _viewId(DomElement? element) {