Add binaryMessenger constructor argument to platform channels (#30406)

* Deprecates `BinaryMessages` in favor of a default instance of `BinaryMessenger`, called `defaultBinaryMessenger`
* Platform channels use the `defaultBinaryMessenger` for their binaryMessenger default argument.

dev/automated_tests/flutter_test/ticker_test.dart

@@ -11,6 +11,6 @@ void main() {
     Ticker((Duration duration) { })..start();
 
     final ByteData message = const StringCodec().encodeMessage('AppLifecycleState.paused');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) {});
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) {});
   });
 }

packages/flutter/lib/services.dart

@@ -11,6 +11,7 @@
 library services;
 
 export 'src/services/asset_bundle.dart';
+export 'src/services/binary_messenger.dart';
 export 'src/services/binding.dart';
 export 'src/services/clipboard.dart';
 export 'src/services/font_loader.dart';

packages/flutter/lib/src/services/asset_bundle.dart

@@ -9,7 +9,7 @@ import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 
-import 'platform_messages.dart';
+import 'binary_messenger.dart';
 
 /// A collection of resources used by the application.
 ///
@@ -216,7 +216,7 @@ class PlatformAssetBundle extends CachingAssetBundle {
   Future<ByteData> load(String key) async {
     final Uint8List encoded = utf8.encoder.convert(Uri(path: Uri.encodeFull(key)).path);
     final ByteData asset =
-        await BinaryMessages.send('flutter/assets', encoded.buffer.asByteData());
+        await defaultBinaryMessenger.send('flutter/assets', encoded.buffer.asByteData());
     if (asset == null)
       throw FlutterError('Unable to load asset: $key');
     return asset;

packages/flutter/lib/src/services/binary_messenger.dart

@@ -0,0 +1,154 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:flutter/foundation.dart';
+
+/// A function which takes a platform message and asynchronously returns an encoded response.
+typedef MessageHandler = Future<ByteData> Function(ByteData message);
+
+/// A messenger which sends binary data across the Flutter platform barrier.
+///
+/// This class also registers handlers for incoming messages.
+abstract class BinaryMessenger {
+  /// A const constructor to allow subclasses to be const.
+  const BinaryMessenger();
+
+  /// Calls the handler registered for the given channel.
+  ///
+  /// Typically called by [ServicesBinding] to handle platform messages received
+  /// from [Window.onPlatformMessage].
+  ///
+  /// To register a handler for a given message channel, see [setMessageHandler].
+  Future<void> handlePlatformMessage(String channel, ByteData data, ui.PlatformMessageResponseCallback callback);
+
+  /// Send a binary message to the platform plugins on the given channel.
+  ///
+  /// Returns a [Future] which completes to the received response, undecoded,
+  /// in binary form.
+  Future<ByteData> send(String channel, ByteData message);
+
+  /// Set a callback for receiving messages from the platform plugins on the
+  /// given channel, without decoding them.
+  ///
+  /// The given callback will replace the currently registered callback for that
+  /// channel, if any. To remove the handler, pass null as the [handler]
+  /// argument.
+  ///
+  /// The handler's return value, if non-null, is sent as a response, unencoded.
+  void setMessageHandler(String channel, Future<ByteData> handler(ByteData message));
+
+  /// Set a mock callback for intercepting messages from the [send] method on
+  /// this class, on the given channel, without decoding them.
+  ///
+  /// The given callback will replace the currently registered mock callback for
+  /// that channel, if any. To remove the mock handler, pass null as the
+  /// [handler] argument.
+  ///
+  /// The handler's return value, if non-null, is used as a response, unencoded.
+  ///
+  /// This is intended for testing. Messages intercepted in this manner are not
+  /// sent to platform plugins.
+  void setMockMessageHandler(String channel, Future<ByteData> handler(ByteData message));
+}
+
+/// The default implementation of [BinaryMessenger].
+///
+/// This messenger sends messages from the app-side to the platform-side and
+/// dispatches incoming messages from the platform-side to the appropriate
+/// handler.
+class _DefaultBinaryMessenger extends BinaryMessenger {
+  const _DefaultBinaryMessenger._();
+
+  // Handlers for incoming messages from platform plugins.
+  // This is static so that this class can have a const constructor.
+  static final Map<String, MessageHandler> _handlers =
+      <String, MessageHandler>{};
+
+  // Mock handlers that intercept and respond to outgoing messages.
+  // This is static so that this class can have a const constructor.
+  static final Map<String, MessageHandler> _mockHandlers =
+      <String, MessageHandler>{};
+
+  Future<ByteData> _sendPlatformMessage(String channel, ByteData message) {
+    final Completer<ByteData> completer = Completer<ByteData>();
+    // ui.window is accessed directly instead of using ServicesBinding.instance.window
+    // because this method might be invoked before any binding is initialized.
+    // This issue was reported in #27541. It is not ideal to statically access
+    // ui.window because the Window may be dependency injected elsewhere with
+    // a different instance. However, static access at this location seems to be
+    // the least bad option.
+    ui.window.sendPlatformMessage(channel, message, (ByteData reply) {
+      try {
+        completer.complete(reply);
+      } catch (exception, stack) {
+        FlutterError.reportError(FlutterErrorDetails(
+          exception: exception,
+          stack: stack,
+          library: 'services library',
+          context: ErrorDescription('during a platform message response callback'),
+        ));
+      }
+    });
+    return completer.future;
+  }
+
+  @override
+  Future<void> handlePlatformMessage(
+    String channel,
+    ByteData data,
+    ui.PlatformMessageResponseCallback callback,
+  ) async {
+    ByteData response;
+    try {
+      final MessageHandler handler = _handlers[channel];
+      if (handler != null)
+        response = await handler(data);
+    } catch (exception, stack) {
+      FlutterError.reportError(FlutterErrorDetails(
+        exception: exception,
+        stack: stack,
+        library: 'services library',
+        context: ErrorDescription('during a platform message callback'),
+      ));
+    } finally {
+      callback(response);
+    }
+  }
+
+
+  @override
+  Future<ByteData> send(String channel, ByteData message) {
+    final MessageHandler handler = _mockHandlers[channel];
+    if (handler != null)
+      return handler(message);
+    return _sendPlatformMessage(channel, message);
+  }
+
+  @override
+  void setMessageHandler(String channel, MessageHandler handler) {
+    if (handler == null)
+      _handlers.remove(channel);
+    else
+      _handlers[channel] = handler;
+  }
+
+  @override
+  void setMockMessageHandler(String channel, MessageHandler handler) {
+    if (handler == null)
+      _mockHandlers.remove(channel);
+    else
+      _mockHandlers[channel] = handler;
+  }
+}
+
+/// The default instance of [BinaryMessenger].
+///
+/// This is used to send messages from the application to the platform, and
+/// keeps track of which handlers have been registered on each channel so
+/// it may dispatch incoming messages to the registered handler.
+const BinaryMessenger defaultBinaryMessenger = _DefaultBinaryMessenger._();

packages/flutter/lib/src/services/binding.dart

@@ -7,9 +7,9 @@ import 'dart:async';
 import 'package:flutter/foundation.dart';
 
 import 'asset_bundle.dart';
-import 'platform_messages.dart';
+import 'binary_messenger.dart';
 
-/// Listens for platform messages and directs them to [BinaryMessages].
+/// Listens for platform messages and directs them to the [defaultBinaryMessenger].
 ///
 /// The [ServicesBinding] also registers a [LicenseEntryCollector] that exposes
 /// the licenses found in the `LICENSE` file stored at the root of the asset
@@ -21,7 +21,7 @@ mixin ServicesBinding on BindingBase {
     super.initInstances();
     _instance = this;
     window
-      ..onPlatformMessage = BinaryMessages.handlePlatformMessage;
+      ..onPlatformMessage = defaultBinaryMessenger.handlePlatformMessage;
     initLicenses();
   }
 

packages/flutter/lib/src/services/platform_channel.dart

@@ -7,9 +7,9 @@ import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 
+import 'binary_messenger.dart';
 import 'message_codec.dart';
 import 'message_codecs.dart';
-import 'platform_messages.dart';
 
 /// A named channel for communicating with platform plugins using asynchronous
 /// message passing.
@@ -29,10 +29,13 @@ import 'platform_messages.dart';
 ///
 /// See: <https://flutter.dev/platform-channels/>
 class BasicMessageChannel<T> {
-  /// Creates a [BasicMessageChannel] with the specified [name] and [codec].
+  /// Creates a [BasicMessageChannel] with the specified [name], [codec] and [binaryMessenger].
   ///
-  /// Neither [name] nor [codec] may be null.
+  /// None of [name], [codec], or [binaryMessenger] may be null.
-  const BasicMessageChannel(this.name, this.codec);
+  const BasicMessageChannel(this.name, this.codec, { this.binaryMessenger = defaultBinaryMessenger })
+    : assert(name != null),
+      assert(codec != null),
+      assert(binaryMessenger != null);
 
   /// The logical channel on which communication happens, not null.
   final String name;
@@ -40,12 +43,15 @@ class BasicMessageChannel<T> {
   /// The message codec used by this channel, not null.
   final MessageCodec<T> codec;
 
+  /// The messenger which sends the bytes for this channel, not null.
+  final BinaryMessenger binaryMessenger;
+
   /// Sends the specified [message] to the platform plugins on this channel.
   ///
   /// Returns a [Future] which completes to the received response, which may
   /// be null.
   Future<T> send(T message) async {
-    return codec.decodeMessage(await BinaryMessages.send(name, codec.encodeMessage(message)));
+    return codec.decodeMessage(await binaryMessenger.send(name, codec.encodeMessage(message)));
   }
 
   /// Sets a callback for receiving messages from the platform plugins on this
@@ -59,9 +65,9 @@ class BasicMessageChannel<T> {
   /// message reply. It may be null.
   void setMessageHandler(Future<T> handler(T message)) {
     if (handler == null) {
-      BinaryMessages.setMessageHandler(name, null);
+      binaryMessenger.setMessageHandler(name, null);
     } else {
-      BinaryMessages.setMessageHandler(name, (ByteData message) async {
+      binaryMessenger.setMessageHandler(name, (ByteData message) async {
         return codec.encodeMessage(await handler(codec.decodeMessage(message)));
       });
     }
@@ -80,9 +86,9 @@ class BasicMessageChannel<T> {
   /// sent to platform plugins.
   void setMockMessageHandler(Future<T> handler(T message)) {
     if (handler == null) {
-      BinaryMessages.setMockMessageHandler(name, null);
+      binaryMessenger.setMockMessageHandler(name, null);
     } else {
-      BinaryMessages.setMockMessageHandler(name, (ByteData message) async {
+      binaryMessenger.setMockMessageHandler(name, (ByteData message) async {
         return codec.encodeMessage(await handler(codec.decodeMessage(message)));
       });
     }
@@ -112,8 +118,11 @@ class MethodChannel {
   /// The [codec] used will be [StandardMethodCodec], unless otherwise
   /// specified.
   ///
-  /// Neither [name] nor [codec] may be null.
+  /// None of [name], [binaryMessenger], or [codec] may be null.
-  const MethodChannel(this.name, [this.codec = const StandardMethodCodec()]);
+  const MethodChannel(this.name, [this.codec = const StandardMethodCodec(), this.binaryMessenger = defaultBinaryMessenger ])
+    : assert(name != null),
+      assert(binaryMessenger != null),
+      assert(codec != null);
 
   /// The logical channel on which communication happens, not null.
   final String name;
@@ -121,6 +130,11 @@ class MethodChannel {
   /// The message codec used by this channel, not null.
   final MethodCodec codec;
 
+  /// The messenger used by this channel to send platform messages.
+  ///
+  /// The messenger may not be null.
+  final BinaryMessenger binaryMessenger;
+
   /// Invokes a [method] on this channel with the specified [arguments].
   ///
   /// The static type of [arguments] is `dynamic`, but only values supported by
@@ -287,12 +301,12 @@ class MethodChannel {
   ///    [StandardMethodCodec].
   ///  * [JSONMessageCodec] which defines the payload values supported by
   ///    [JSONMethodCodec].
-  ///  * <https://docs.flutter.io/javadoc/io/flutter/plugin/common/MethodCall.html>
+  ///  * <https://api.flutter.dev/javadoc/io/flutter/plugin/common/MethodCall.html>
   ///    for how to access method call arguments on Android.
   @optionalTypeArgs
   Future<T> invokeMethod<T>(String method, [ dynamic arguments ]) async {
     assert(method != null);
-    final ByteData result = await BinaryMessages.send(
+    final ByteData result = await binaryMessenger.send(
       name,
       codec.encodeMethodCall(MethodCall(method, arguments)),
     );
@@ -346,7 +360,7 @@ class MethodChannel {
   /// similarly to what happens if no method call handler has been set.
   /// Any other exception results in an error envelope being sent.
   void setMethodCallHandler(Future<dynamic> handler(MethodCall call)) {
-    BinaryMessages.setMessageHandler(
+    binaryMessenger.setMessageHandler(
       name,
       handler == null ? null : (ByteData message) => _handleAsMethodCall(message, handler),
     );
@@ -371,7 +385,7 @@ class MethodChannel {
   /// [MethodCodec.encodeSuccessEnvelope], to act as if platform plugin had
   /// returned that value.
   void setMockMethodCallHandler(Future<dynamic> handler(MethodCall call)) {
-    BinaryMessages.setMockMessageHandler(
+    binaryMessenger.setMockMessageHandler(
       name,
       handler == null ? null : (ByteData message) => _handleAsMethodCall(message, handler),
     );
@@ -474,7 +488,7 @@ class EventChannel {
     final MethodChannel methodChannel = MethodChannel(name, codec);
     StreamController<dynamic> controller;
     controller = StreamController<dynamic>.broadcast(onListen: () async {
-      BinaryMessages.setMessageHandler(name, (ByteData reply) async {
+      defaultBinaryMessenger.setMessageHandler(name, (ByteData reply) async {
         if (reply == null) {
           controller.close();
         } else {
@@ -497,7 +511,7 @@ class EventChannel {
         ));
       }
     }, onCancel: () async {
-      BinaryMessages.setMessageHandler(name, null);
+      defaultBinaryMessenger.setMessageHandler(name, null);
       try {
         await methodChannel.invokeMethod<void>('cancel', arguments);
       } catch (exception, stack) {

packages/flutter/lib/src/services/platform_messages.dart

@@ -6,17 +6,18 @@ import 'dart:async';
 import 'dart:typed_data';
 import 'dart:ui' as ui;
 
-import 'package:flutter/foundation.dart';
+import 'binary_messenger.dart';
-
 import 'binding.dart' show ServicesBinding;
 import 'platform_channel.dart';
 
-typedef _MessageHandler = Future<ByteData> Function(ByteData message);
-
 /// Sends binary messages to and receives binary messages from platform plugins.
 ///
+/// This class has been deprecated in favor of [defaultBinaryMessenger]. New
+/// code should not use [BinaryMessages].
+///
 /// See also:
 ///
+///  * [BinaryMessenger], the interface which has replaced this class.
 ///  * [BasicMessageChannel], which provides basic messaging services similar to
 ///    `BinaryMessages`, but with pluggable message codecs in support of sending
 ///    strings or semi-structured messages.
@@ -24,77 +25,34 @@ typedef _MessageHandler = Future<ByteData> Function(ByteData message);
 ///    method calls.
 ///  * [EventChannel], which provides platform communication using event streams.
 ///  * <https://flutter.dev/platform-channels/>
+@Deprecated('This class, which was just a collection of static methods, has been '
+            'deprecated in favor of BinaryMessenger, and its default '
+            'implementation, defaultBinaryMessenger.')
 class BinaryMessages {
   BinaryMessages._();
 
-  // Handlers for incoming messages from platform plugins.
-  static final Map<String, _MessageHandler> _handlers =
-      <String, _MessageHandler>{};
-
-  // Mock handlers that intercept and respond to outgoing messages.
-  static final Map<String, _MessageHandler> _mockHandlers =
-      <String, _MessageHandler>{};
-
-  static Future<ByteData> _sendPlatformMessage(String channel, ByteData message) {
-    final Completer<ByteData> completer = Completer<ByteData>();
-    // ui.window is accessed directly instead of using ServicesBinding.instance.window
-    // because this method might be invoked before any binding is initialized.
-    // This issue was reported in #27541. It is not ideal to statically access
-    // ui.window because the Window may be dependency injected elsewhere with
-    // a different instance. However, static access at this location seems to be
-    // the least bad option.
-    ui.window.sendPlatformMessage(channel, message, (ByteData reply) {
-      try {
-        completer.complete(reply);
-      } catch (exception, stack) {
-        FlutterError.reportError(FlutterErrorDetails(
-          exception: exception,
-          stack: stack,
-          library: 'services library',
-          context: ErrorDescription('during a platform message response callback'),
-        ));
-      }
-    });
-    return completer.future;
-  }
-
   /// Calls the handler registered for the given channel.
   ///
   /// Typically called by [ServicesBinding] to handle platform messages received
   /// from [Window.onPlatformMessage].
   ///
   /// To register a handler for a given message channel, see [setMessageHandler].
+  @Deprecated('Use defaultBinaryMessenger.handlePlatformMessage instead.')
   static Future<void> handlePlatformMessage(
     String channel,
     ByteData data,
     ui.PlatformMessageResponseCallback callback,
-  ) async {
+  ) {
-    ByteData response;
+    return defaultBinaryMessenger.handlePlatformMessage(channel, data, callback);
-    try {
-      final _MessageHandler handler = _handlers[channel];
-      if (handler != null)
-        response = await handler(data);
-    } catch (exception, stack) {
-      FlutterError.reportError(FlutterErrorDetails(
-        exception: exception,
-        stack: stack,
-        library: 'services library',
-        context: ErrorDescription('during a platform message callback'),
-      ));
-    } finally {
-      callback(response);
-    }
   }
 
   /// Send a binary message to the platform plugins on the given channel.
   ///
   /// Returns a [Future] which completes to the received response, undecoded, in
   /// binary form.
+  @Deprecated('Use defaultBinaryMessenger.send instead.')
   static Future<ByteData> send(String channel, ByteData message) {
-    final _MessageHandler handler = _mockHandlers[channel];
+    return defaultBinaryMessenger.send(channel, message);
-    if (handler != null)
-      return handler(message);
-    return _sendPlatformMessage(channel, message);
   }
 
   /// Set a callback for receiving messages from the platform plugins on the
@@ -105,11 +63,9 @@ class BinaryMessages {
   /// argument.
   ///
   /// The handler's return value, if non-null, is sent as a response, unencoded.
+  @Deprecated('Use defaultBinaryMessenger.setMessageHandler instead.')
   static void setMessageHandler(String channel, Future<ByteData> handler(ByteData message)) {
-    if (handler == null)
+    defaultBinaryMessenger.setMessageHandler(channel, handler);
-      _handlers.remove(channel);
-    else
-      _handlers[channel] = handler;
   }
 
   /// Set a mock callback for intercepting messages from the `send*` methods on
@@ -123,10 +79,8 @@ class BinaryMessages {
   ///
   /// This is intended for testing. Messages intercepted in this manner are not
   /// sent to platform plugins.
+  @Deprecated('Use defaultBinaryMessenger.setMockMessageHandler instead.')
   static void setMockMessageHandler(String channel, Future<ByteData> handler(ByteData message)) {
-    if (handler == null)
+    defaultBinaryMessenger.setMockMessageHandler(channel, handler);
-      _mockHandlers.remove(channel);
-    else
-      _mockHandlers[channel] = handler;
   }
 }

packages/flutter/test/foundation/service_extensions_test.dart

@@ -417,7 +417,7 @@ void main() {
     bool completed;
 
     completed = false;
-    BinaryMessages.setMockMessageHandler('flutter/assets', (ByteData message) async {
+    defaultBinaryMessenger.setMockMessageHandler('flutter/assets', (ByteData message) async {
       expect(utf8.decode(message.buffer.asUint8List()), 'test');
       completed = true;
       return ByteData(5); // 0x0000000000
@@ -436,7 +436,7 @@ void main() {
     data = await rootBundle.loadStructuredData<bool>('test', (String value) async { expect(value, '\x00\x00\x00\x00\x00'); return false; });
     expect(data, isFalse);
     expect(completed, isTrue);
-    BinaryMessages.setMockMessageHandler('flutter/assets', null);
+    defaultBinaryMessenger.setMockMessageHandler('flutter/assets', null);
   });
 
   test('Service extensions - exit', () async {

packages/flutter/test/material/search_test.dart

@@ -72,7 +72,7 @@ void main() {
 
     // Simulate system back button
     final ByteData message = const JSONMethodCodec().encodeMethodCall(const MethodCall('popRoute'));
-    await BinaryMessages.handlePlatformMessage('flutter/navigation', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/navigation', message, (_) { });
     await tester.pumpAndSettle();
 
     expect(selectedResults, <void>[null]);

packages/flutter/test/material/text_field_test.dart

@@ -2957,7 +2957,7 @@ void main() {
   });
 
   void sendFakeKeyEvent(Map<String, dynamic> data) {
-    BinaryMessages.handlePlatformMessage(
+    defaultBinaryMessenger.handlePlatformMessage(
       SystemChannels.keyEvent.name,
       SystemChannels.keyEvent.codec.encodeMessage(data),
           (ByteData data) { },

packages/flutter/test/scheduler/ticker_test.dart

@@ -129,7 +129,7 @@ void main() {
     expect(tickCount, equals(0));
 
     final ByteData message = const StringCodec().encodeMessage('AppLifecycleState.paused');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(ticker.isTicking, isFalse);
     expect(ticker.isActive, isTrue);
 
@@ -138,7 +138,7 @@ void main() {
 
   testWidgets('Ticker can be created before application unpauses', (WidgetTester tester) async {
     final ByteData pausedMessage = const StringCodec().encodeMessage('AppLifecycleState.paused');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', pausedMessage, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', pausedMessage, (_) { });
 
     int tickCount = 0;
     void handleTick(Duration duration) {
@@ -157,7 +157,7 @@ void main() {
     expect(ticker.isTicking, isFalse);
 
     final ByteData resumedMessage = const StringCodec().encodeMessage('AppLifecycleState.resumed');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', resumedMessage, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', resumedMessage, (_) { });
 
     await tester.pump(const Duration(milliseconds: 10));
 

packages/flutter/test/services/fake_platform_views.dart

@@ -35,7 +35,7 @@ class FakeAndroidPlatformViewsController {
   void invokeViewFocused(int viewId) {
     final MethodCodec codec = SystemChannels.platform_views.codec;
     final ByteData data = codec.encodeMethodCall(MethodCall('viewFocused', viewId));
-    BinaryMessages.handlePlatformMessage(SystemChannels.platform_views.name, data, (ByteData data) {});
+    defaultBinaryMessenger.handlePlatformMessage(SystemChannels.platform_views.name, data, (ByteData data) {});
   }
 
   Future<dynamic> _onMethodCall(MethodCall call) {

packages/flutter/test/services/platform_channel_test.dart

@@ -13,7 +13,7 @@ void main() {
     const MessageCodec<String> string = StringCodec();
     const BasicMessageChannel<String> channel = BasicMessageChannel<String>('ch', string);
     test('can send string message and get reply', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch',
         (ByteData message) async => string.encodeMessage(string.decodeMessage(message) + ' world'),
       );
@@ -23,7 +23,7 @@ void main() {
     test('can receive string message and send reply', () async {
       channel.setMessageHandler((String message) async => message + ' world');
       String reply;
-      await BinaryMessages.handlePlatformMessage(
+      await defaultBinaryMessenger.handlePlatformMessage(
         'ch',
         const StringCodec().encodeMessage('hello'),
         (ByteData replyBinary) {
@@ -39,7 +39,7 @@ void main() {
     const MethodCodec jsonMethod = JSONMethodCodec();
     const MethodChannel channel = MethodChannel('ch7', jsonMethod);
     test('can invoke method and get result', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch7',
         (ByteData message) async {
           final Map<dynamic, dynamic> methodCall = jsonMessage.decodeMessage(message);
@@ -54,7 +54,7 @@ void main() {
       expect(result, equals('hello world'));
     });
     test('can invoke list method and get result', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch7',
         (ByteData message) async {
           final Map<dynamic, dynamic> methodCall = jsonMessage.decodeMessage(message);
@@ -70,7 +70,7 @@ void main() {
     });
 
     test('can invoke list method and get null result', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch7',
         (ByteData message) async {
           final Map<dynamic, dynamic> methodCall = jsonMessage.decodeMessage(message);
@@ -86,7 +86,7 @@ void main() {
 
 
     test('can invoke map method and get result', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch7',
         (ByteData message) async {
           final Map<dynamic, dynamic> methodCall = jsonMessage.decodeMessage(message);
@@ -102,7 +102,7 @@ void main() {
     });
 
     test('can invoke map method and get null result', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch7',
         (ByteData message) async {
           final Map<dynamic, dynamic> methodCall = jsonMessage.decodeMessage(message);
@@ -117,7 +117,7 @@ void main() {
     });
 
     test('can invoke method and get error', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch7',
         (ByteData message) async {
           return jsonMessage.encodeMessage(<dynamic>[
@@ -139,7 +139,7 @@ void main() {
       }
     });
     test('can invoke unimplemented method', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch7',
         (ByteData message) async => null,
       );
@@ -157,7 +157,7 @@ void main() {
       channel.setMethodCallHandler(null);
       final ByteData call = jsonMethod.encodeMethodCall(const MethodCall('sayHello', 'hello'));
       ByteData envelope;
-      await BinaryMessages.handlePlatformMessage('ch7', call, (ByteData result) {
+      await defaultBinaryMessenger.handlePlatformMessage('ch7', call, (ByteData result) {
         envelope = result;
       });
       expect(envelope, isNull);
@@ -168,7 +168,7 @@ void main() {
       });
       final ByteData call = jsonMethod.encodeMethodCall(const MethodCall('sayHello', 'hello'));
       ByteData envelope;
-      await BinaryMessages.handlePlatformMessage('ch7', call, (ByteData result) {
+      await defaultBinaryMessenger.handlePlatformMessage('ch7', call, (ByteData result) {
         envelope = result;
       });
       expect(envelope, isNull);
@@ -177,7 +177,7 @@ void main() {
       channel.setMethodCallHandler((MethodCall call) async => '${call.arguments}, world');
       final ByteData call = jsonMethod.encodeMethodCall(const MethodCall('sayHello', 'hello'));
       ByteData envelope;
-      await BinaryMessages.handlePlatformMessage('ch7', call, (ByteData result) {
+      await defaultBinaryMessenger.handlePlatformMessage('ch7', call, (ByteData result) {
         envelope = result;
       });
       expect(jsonMethod.decodeEnvelope(envelope), equals('hello, world'));
@@ -188,7 +188,7 @@ void main() {
       });
       final ByteData call = jsonMethod.encodeMethodCall(const MethodCall('sayHello', 'hello'));
       ByteData envelope;
-      await BinaryMessages.handlePlatformMessage('ch7', call, (ByteData result) {
+      await defaultBinaryMessenger.handlePlatformMessage('ch7', call, (ByteData result) {
         envelope = result;
       });
       try {
@@ -207,7 +207,7 @@ void main() {
       });
       final ByteData call = jsonMethod.encodeMethodCall(const MethodCall('sayHello', 'hello'));
       ByteData envelope;
-      await BinaryMessages.handlePlatformMessage('ch7', call, (ByteData result) {
+      await defaultBinaryMessenger.handlePlatformMessage('ch7', call, (ByteData result) {
         envelope = result;
       });
       try {
@@ -226,7 +226,7 @@ void main() {
     const MethodCodec jsonMethod = JSONMethodCodec();
     const EventChannel channel = EventChannel('ch', jsonMethod);
     void emitEvent(dynamic event) {
-      BinaryMessages.handlePlatformMessage(
+      defaultBinaryMessenger.handlePlatformMessage(
         'ch',
         event,
             (ByteData reply) { },
@@ -234,7 +234,7 @@ void main() {
     }
     test('can receive event stream', () async {
       bool canceled = false;
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch',
         (ByteData message) async {
           final Map<dynamic, dynamic> methodCall = jsonMessage.decodeMessage(message);
@@ -258,7 +258,7 @@ void main() {
       expect(canceled, isTrue);
     });
     test('can receive error event', () async {
-      BinaryMessages.setMockMessageHandler(
+      defaultBinaryMessenger.setMockMessageHandler(
         'ch',
         (ByteData message) async {
           final Map<dynamic, dynamic> methodCall = jsonMessage.decodeMessage(message);

packages/flutter/test/services/platform_messages_test.dart

@@ -9,23 +9,23 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   test('Mock binary message handler control test', () async {
-    // Initialize all bindings because BinaryMessages.send() needs a window.
+    // Initialize all bindings because defaultBinaryMessenger.send() needs a window.
     TestWidgetsFlutterBinding.ensureInitialized();
 
     final List<ByteData> log = <ByteData>[];
 
-    BinaryMessages.setMockMessageHandler('test1', (ByteData message) async {
+    defaultBinaryMessenger.setMockMessageHandler('test1', (ByteData message) async {
       log.add(message);
       return null;
     });
 
     final ByteData message = ByteData(2)..setUint16(0, 0xABCD);
-    await BinaryMessages.send('test1', message);
+    await defaultBinaryMessenger.send('test1', message);
     expect(log, equals(<ByteData>[message]));
     log.clear();
 
-    BinaryMessages.setMockMessageHandler('test1', null);
+    defaultBinaryMessenger.setMockMessageHandler('test1', null);
-    await BinaryMessages.send('test1', message);
+    await defaultBinaryMessenger.send('test1', message);
     expect(log, isEmpty);
   });
 }

packages/flutter/test/services/system_chrome_test.dart

@@ -61,7 +61,7 @@ void main() {
   test('setApplicationSwitcherDescription missing plugin', () async {
     final List<ByteData> log = <ByteData>[];
 
-    BinaryMessages.setMockMessageHandler('flutter/platform', (ByteData message) {
+    defaultBinaryMessenger.setMockMessageHandler('flutter/platform', (ByteData message) {
       log.add(message);
       return null;
     });

packages/flutter/test/widgets/binding_test.dart

@@ -46,7 +46,7 @@ void main() {
     WidgetsBinding.instance.addObserver(observer);
     final ByteData message = const JSONMessageCodec().encodeMessage(
       <String, dynamic>{'type': 'memoryPressure'});
-    await BinaryMessages.handlePlatformMessage('flutter/system', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/system', message, (_) { });
     expect(observer.sawMemoryPressure, true);
     WidgetsBinding.instance.removeObserver(observer);
   });
@@ -56,19 +56,19 @@ void main() {
     WidgetsBinding.instance.addObserver(observer);
 
     ByteData message = const StringCodec().encodeMessage('AppLifecycleState.paused');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(observer.lifecycleState, AppLifecycleState.paused);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.resumed');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(observer.lifecycleState, AppLifecycleState.resumed);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.inactive');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(observer.lifecycleState, AppLifecycleState.inactive);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.suspending');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(observer.lifecycleState, AppLifecycleState.suspending);
   });
 
@@ -79,7 +79,7 @@ void main() {
     const String testRouteName = 'testRouteName';
     final ByteData message = const JSONMethodCodec().encodeMethodCall(
       const MethodCall('pushRoute', testRouteName));
-    await BinaryMessages.handlePlatformMessage('flutter/navigation', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/navigation', message, (_) { });
     expect(observer.pushedRoute, testRouteName);
 
     WidgetsBinding.instance.removeObserver(observer);
@@ -90,31 +90,31 @@ void main() {
     expect(tester.binding.hasScheduledFrame, isFalse);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.paused');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(tester.binding.hasScheduledFrame, isFalse);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.resumed');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(tester.binding.hasScheduledFrame, isTrue);
     await tester.pump();
     expect(tester.binding.hasScheduledFrame, isFalse);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.inactive');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(tester.binding.hasScheduledFrame, isFalse);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.suspending');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(tester.binding.hasScheduledFrame, isFalse);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.inactive');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(tester.binding.hasScheduledFrame, isTrue);
     await tester.pump();
     expect(tester.binding.hasScheduledFrame, isFalse);
 
     message = const StringCodec().encodeMessage('AppLifecycleState.paused');
-    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
+    await defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
     expect(tester.binding.hasScheduledFrame, isFalse);
 
     tester.binding.scheduleFrame();

packages/flutter/test/widgets/focus_manager_test.dart

@@ -10,7 +10,7 @@ import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void sendFakeKeyEvent(Map<String, dynamic> data) {
-  BinaryMessages.handlePlatformMessage(
+  defaultBinaryMessenger.handlePlatformMessage(
     SystemChannels.keyEvent.name,
     SystemChannels.keyEvent.codec.encodeMessage(data),
     (ByteData data) {},

packages/flutter/test/widgets/raw_keyboard_listener_test.dart

@@ -9,7 +9,7 @@ import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void sendFakeKeyEvent(Map<String, dynamic> data) {
-  BinaryMessages.handlePlatformMessage(
+  defaultBinaryMessenger.handlePlatformMessage(
     SystemChannels.keyEvent.name,
     SystemChannels.keyEvent.codec.encodeMessage(data),
     (ByteData data) {},

packages/flutter_test/lib/src/binding.dart

@@ -757,7 +757,7 @@ class AutomatedTestWidgetsFlutterBinding extends TestWidgetsFlutterBinding {
     _ensureInitialized(assetFolderPath);
 
     if (_allowedAssetKeys.isNotEmpty) {
-      BinaryMessages.setMockMessageHandler('flutter/assets', (ByteData message) {
+      defaultBinaryMessenger.setMockMessageHandler('flutter/assets', (ByteData message) {
         final String key = utf8.decode(message.buffer.asUint8List());
         if (_allowedAssetKeys.contains(key)) {
           final File asset = File(path.join(assetFolderPath, key));

packages/flutter_test/lib/src/test_text_input.dart

@@ -105,7 +105,7 @@ class TestTextInput {
     // test this code does not run in a package:test test zone.
     if (_client == 0)
       throw TestFailure('Tried to use TestTextInput with no keyboard attached. You must use WidgetTester.showKeyboard() first.');
-    BinaryMessages.handlePlatformMessage(
+    defaultBinaryMessenger.handlePlatformMessage(
       SystemChannels.textInput.name,
       SystemChannels.textInput.codec.encodeMethodCall(
         MethodCall(
@@ -137,7 +137,7 @@ class TestTextInput {
 
       final Completer<void> completer = Completer<void>();
 
-      BinaryMessages.handlePlatformMessage(
+      defaultBinaryMessenger.handlePlatformMessage(
         SystemChannels.textInput.name,
         SystemChannels.textInput.codec.encodeMethodCall(
           MethodCall(