Add deprecations to PlatformMessage stuff

Author: goderbauer

lib/ui/channel_buffers.dart

@@ -6,13 +6,18 @@
 // KEEP THIS SYNCHRONIZED WITH ../web_ui/lib/channel_buffers.dart
 part of dart.ui;
 
+/// Deprecated. Migrate to [ChannelCallback] isntead.
+///
 /// Signature for [ChannelBuffers.drain]'s `callback` argument.
 ///
 /// The first argument is the data sent by the plugin.
 ///
 /// The second argument is a closure that, when called, will send messages
 /// back to the plugin.
-// TODO(ianh): deprecate this once the framework is migrated to [ChannelCallback].
+@Deprecated(
+  'Migrate to ChannelCallback instead. '
+  'This feature was deprecated after v3.11.0-20.0.pre.',
+)
 typedef DrainChannelCallback = Future<void> Function(ByteData? data, PlatformMessageResponseCallback callback);
 
 /// Signature for [ChannelBuffers.setListener]'s `callback` argument.
@@ -377,14 +382,19 @@ class ChannelBuffers {
     }
   }
 
+  /// Deprecated. Migrate to [setListener] instead.
+  ///
   /// Remove and process all stored messages for a given channel.
   ///
   /// This should be called once a channel is prepared to handle messages
   /// (i.e. when a message handler is set up in the framework).
   ///
   /// The messages are processed by calling the given `callback`. Each message
   /// is processed in its own microtask.
-  // TODO(ianh): deprecate once framework uses [setListener].
+  @Deprecated(
+    'Migrate to setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   Future<void> drain(String name, DrainChannelCallback callback) async {
     final _Channel? channel = _channels[name];
     while (channel != null && !channel._queue.isEmpty) {

lib/ui/platform_dispatcher.dart

@@ -45,8 +45,13 @@ typedef SemanticsActionEventCallback = void Function(SemanticsActionEvent action
 /// [PlatformDispatcher.onPlatformMessage].
 typedef PlatformMessageResponseCallback = void Function(ByteData? data);
 
+/// Deprecated. Migrate to [ChannelBuffers.setListener] instead.
+///
 /// Signature for [PlatformDispatcher.onPlatformMessage].
-// TODO(ianh): deprecate once framework uses [ChannelBuffers.setListener].
+@Deprecated(
+  'Migrate to ChannelBuffers.setListener instead. '
+  'This feature was deprecated after v3.11.0-20.0.pre.',
+)
 typedef PlatformMessageCallback = void Function(String name, ByteData? data, PlatformMessageResponseCallback? callback);
 
 // Signature for _setNeedsReportTimings.
@@ -655,6 +660,8 @@ class PlatformDispatcher {
   @Native<Void Function(Int64)>(symbol: 'PlatformConfigurationNativeApi::RegisterBackgroundIsolate')
   external static void __registerBackgroundIsolate(int rootIsolateId);
 
+  /// Deprecated. Migrate to [ChannelBuffers.setListener] instead.
+  ///
   /// Called whenever this platform dispatcher receives a message from a
   /// platform-specific plugin.
   ///
@@ -668,11 +675,17 @@ class PlatformDispatcher {
   ///
   /// The framework invokes this callback in the same zone in which the callback
   /// was set.
-  // TODO(ianh): Deprecate onPlatformMessage once the framework is moved over
-  // to using channel buffers exclusively.
+  @Deprecated(
+    'Migrate to ChannelBuffers.setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   PlatformMessageCallback? get onPlatformMessage => _onPlatformMessage;
   PlatformMessageCallback? _onPlatformMessage;
   Zone _onPlatformMessageZone = Zone.root;
+  @Deprecated(
+    'Migrate to ChannelBuffers.setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   set onPlatformMessage(PlatformMessageCallback? callback) {
     _onPlatformMessage = callback;
     _onPlatformMessageZone = Zone.current;

lib/ui/window.dart

@@ -802,6 +802,8 @@ class SingletonFlutterWindow extends FlutterView {
     platformDispatcher.sendPlatformMessage(name, data, callback);
   }
 
+  /// Deprecated. Migrate to [ChannelBuffers.setListener] instead.
+  ///
   /// Called whenever this window receives a message from a platform-specific
   /// plugin.
   ///
@@ -817,8 +819,15 @@ class SingletonFlutterWindow extends FlutterView {
   ///
   /// The framework invokes this callback in the same zone in which the
   /// callback was set.
-  // TODO(ianh): deprecate once framework uses [ChannelBuffers.setListener].
+  @Deprecated(
+    'Migrate to ChannelBuffers.setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   PlatformMessageCallback? get onPlatformMessage => platformDispatcher.onPlatformMessage;
+  @Deprecated(
+    'Migrate to ChannelBuffers.setListener instead. '
+    'This feature was deprecated after v3.11.0-20.0.pre.',
+  )
   set onPlatformMessage(PlatformMessageCallback? callback) {
     platformDispatcher.onPlatformMessage = callback;
   }