Revert "Remove deprecated calls to updateSemantics in PlatformDispatcher"

lib/ui/platform_dispatcher.dart

@@ -750,6 +750,27 @@ class PlatformDispatcher {
     _invoke(onAccessibilityFeaturesChanged, _onAccessibilityFeaturesChangedZone,);
   }
 
+  /// Change the retained semantics data about this platform dispatcher.
+  ///
+  /// If [semanticsEnabled] is true, the user has requested that this function
+  /// be called whenever the semantic content of this platform dispatcher
+  /// changes.
+  ///
+  /// In either case, this function disposes the given update, which means the
+  /// semantics update cannot be used further.
+  @Deprecated('''
+    In a multi-view world, the platform dispatcher can no longer provide apis
+    to update semantics since each view will host its own semantics tree.
+
+    Semantics updates must be passed to an individual [FlutterView]. To update
+    semantics, use PlatformDispatcher.instance.views to get a [FlutterView] and
+    call `updateSemantics`.
+  ''')
+  void updateSemantics(SemanticsUpdate update) => _updateSemantics(update);
+
+  @FfiNative<Void Function(Pointer<Void>)>('PlatformConfigurationNativeApi::UpdateSemantics')
+  external static void _updateSemantics(SemanticsUpdate update);
+
   /// The system-reported default locale of the device.
   ///
   /// This establishes the language and formatting conventions that application

lib/web_ui/lib/platform_dispatcher.dart

@@ -83,6 +83,14 @@ abstract class PlatformDispatcher {
   VoidCallback? get onAccessibilityFeaturesChanged;
   set onAccessibilityFeaturesChanged(VoidCallback? callback);
 
+  @Deprecated('''
+    In a multi-view world, the platform dispatcher can no longer provide apis
+    to update semantics since each view will host its own semantics tree.
+
+    Semantics updates must be passed to an individual [FlutterView]. To update
+    semantics, use PlatformDispatcher.instance.views to get a [FlutterView] and
+    call `updateSemantics`.
+  ''')
   void updateSemantics(SemanticsUpdate update);
 
   Locale get locale;

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

@@ -690,7 +690,22 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
         _onAccessibilityFeaturesChanged, _onAccessibilityFeaturesChangedZone);
   }
 
+  /// Change the retained semantics data about this window.
+  ///
+  /// If [semanticsEnabled] is true, the user has requested that this function
+  /// be called whenever the semantic content of this window changes.
+  ///
+  /// In either case, this function disposes the given update, which means the
+  /// semantics update cannot be used further.
   @override
+  @Deprecated('''
+    In a multi-view world, the platform dispatcher can no longer provide apis
+    to update semantics since each view will host its own semantics tree.
+
+    Semantics updates must be passed to an individual [FlutterView]. To update
+    semantics, use PlatformDispatcher.instance.views to get a [FlutterView] and
+    call `updateSemantics`.
+  ''')
   void updateSemantics(ui.SemanticsUpdate update) {
     EngineSemanticsOwner.instance.updateSemantics(update);
   }