Update engine and Mojo usage (#4258)

The new mojom.dart code makes mocking services a bit tricky. I've filed
https://github.com/domokit/mojo/issues/786 about improving that.

bin/cache/engine.version

-cc2cc42f2d3a56c9176f5a2de02b8993a046f88d
+b6ad88501f8f712c4181811c05d37afcf8d52168

examples/layers/services/media_service.dart

@@ -4,7 +4,7 @@
 
 import 'dart:async';
 
-import 'package:sky_services/media/media.mojom.dart';
+import 'package:sky_services/media/media.mojom.dart' as mojom;
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
@@ -24,25 +24,25 @@ class PianoKey {
   final Color color;
   final String soundUrl;
 
-  final MediaPlayerProxy player = new MediaPlayerProxy.unbound();
+  final mojom.MediaPlayerProxy player = new mojom.MediaPlayerProxy.unbound();
 
-  bool get isPlayerOpen => player.impl.isOpen;
+  bool get isPlayerOpen => player.ctrl.isOpen;
 
   void down() {
     if (!isPlayerOpen) return;
-    player.ptr.seekTo(0);
-    player.ptr.start();
+    player.seekTo(0);
+    player.start();
   }
 
   void up() {
     if (!isPlayerOpen) return;
-    player.ptr.pause();
+    player.pause();
   }
 
-  Future<Null> load(MediaServiceProxy mediaService) async {
+  Future<Null> load(mojom.MediaServiceProxy mediaService) async {
     try {
-      mediaService.ptr.createPlayer(player);
-      await player.ptr.prepare(await http.readDataPipe(soundUrl));
+      mediaService.createPlayer(player);
+      await player.prepare(await http.readDataPipe(soundUrl));
     } catch (e) {
       print("Error: failed to load sound file $soundUrl");
       player.close();
@@ -61,9 +61,10 @@ class PianoApp extends StatelessWidget {
   ];
 
   Future<Null> loadSounds() async {
-    MediaServiceProxy mediaService = new MediaServiceProxy.unbound();
+    mojom.MediaServiceProxy mediaService = shell.connectToApplicationService(
+      'mojo:media_service', mojom.MediaService.connectToService
+    );
     try {
-      shell.connectToService("mojo:media_service", mediaService);
       List<Future<Null>> pending = <Future<Null>>[];
       for (PianoKey key in keys)
         pending.add(key.load(mediaService));

packages/flutter/lib/src/http/mojo_client.dart

@@ -135,8 +135,8 @@ class MojoClient {
     mojom.UrlRequest request = _prepareRequest('GET', url, headers);
     mojom.UrlResponse response;
     try {
-      networkService.ptr.createUrlLoader(loader);
-      response = (await loader.ptr.start(request)).response;
+      networkService.createUrlLoader(loader);
+      response = (await loader.start(request)).response;
     } catch (exception, stack) {
       FlutterError.reportError(new FlutterErrorDetails(
         exception: exception,
@@ -181,8 +181,8 @@ class MojoClient {
     mojom.UrlLoaderProxy loader = new mojom.UrlLoaderProxy.unbound();
     mojom.UrlRequest request = _prepareRequest(method, url, headers, body, encoding);
     try {
-      networkService.ptr.createUrlLoader(loader);
-      mojom.UrlResponse response = (await loader.ptr.start(request)).response;
+      networkService.createUrlLoader(loader);
+      mojom.UrlResponse response = (await loader.start(request)).response;
       ByteData data = await mojo.DataPipeDrainer.drainHandle(response.body);
       Uint8List bodyBytes = new Uint8List.view(data.buffer);
       Map<String, String> headers = <String, String>{};
@@ -215,9 +215,7 @@ class MojoClient {
   }
 
   static mojom.NetworkServiceProxy _initNetworkService() {
-    mojom.NetworkServiceProxy proxy = new mojom.NetworkServiceProxy.unbound();
-    shell.connectToService("mojo:authenticated_network_service", proxy);
-    return proxy;
+    return shell.connectToApplicationService('mojo:authenticated_network_service', mojom.NetworkService.connectToService);
   }
 
   /// A handle to the [NetworkService] object used by [MojoClient].

packages/flutter/lib/src/rendering/child_view.dart

@@ -34,15 +34,15 @@ mojom.ViewProxy _initViewProxy() {
 // view keys, which means any scheme for sharing the view host also needs to
 // provide a mechanism for coordinating about view keys.
 final mojom.ViewProxy _viewProxy = _initViewProxy();
-final mojom.View _view = _viewProxy?.ptr;
+final mojom.View _view = _viewProxy;
 
 mojom.ViewContainer _initViewContainer() {
   if (_view == null)
     return null;
   mojom.ViewContainerProxy viewContainerProxy = new mojom.ViewContainerProxy.unbound();
   _view.getContainer(viewContainerProxy);
-  viewContainerProxy.ptr.setListener(new mojom.ViewContainerListenerStub.unbound()..impl = _ViewContainerListenerImpl.instance);
-  return viewContainerProxy.ptr;
+  viewContainerProxy.setListener(new mojom.ViewContainerListenerStub.unbound()..impl = _ViewContainerListenerImpl.instance);
+  return viewContainerProxy;
 }
 
 final mojom.ViewContainer _viewContainer = _initViewContainer();
@@ -75,12 +75,13 @@ class _ViewContainerListenerImpl extends mojom.ViewContainerListener {
 class ChildViewConnection {
   /// Establishes a connection to the app at the given URL.
   ChildViewConnection({ String url }) {
-    mojom.ViewProviderProxy viewProvider = new mojom.ViewProviderProxy.unbound();
-    shell.connectToService(url, viewProvider);
+    mojom.ViewProviderProxy viewProvider = shell.connectToApplicationService(
+      url, mojom.ViewProvider.connectToService
+    );
     mojom.ServiceProviderProxy incomingServices = new mojom.ServiceProviderProxy.unbound();
     mojom.ServiceProviderStub outgoingServices = new mojom.ServiceProviderStub.unbound();
     _viewOwner = new mojom.ViewOwnerProxy.unbound();
-    viewProvider.ptr.createView(_viewOwner, incomingServices, outgoingServices);
+    viewProvider.createView(_viewOwner, incomingServices, outgoingServices);
     viewProvider.close();
     _connection = new ApplicationConnection(outgoingServices, incomingServices);
   }

packages/flutter/lib/src/rendering/semantics.dart

@@ -552,7 +552,7 @@ class SemanticsServer extends mojom.SemanticsServer {
   void addSemanticsListener(mojom.SemanticsListenerProxy listener) {
     // TODO(abarth): We should remove the listener when this pipe closes.
     // See <https://github.com/flutter/flutter/issues/3342>.
-    SemanticsNode.addListener(listener.ptr);
+    SemanticsNode.addListener(listener);
   }
 
   @override

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

@@ -36,13 +36,11 @@ const int NEW_TASK = 0x10000000; // ignore: constant_identifier_names
 const int MULTIPLE_TASK = 0x08000000; // ignore: constant_identifier_names
 
 ActivityProxy _initActivityProxy() {
-  ActivityProxy activity = new ActivityProxy.unbound();
-  shell.connectToService("mojo:android", activity);
-  return activity;
+  return shell.connectToApplicationService('mojo:android', Activity.connectToService);
 }
 
 final ActivityProxy _activityProxy = _initActivityProxy();
-final Activity activity = _activityProxy.ptr;
+final Activity activity = _activityProxy;
 
 Color _cachedPrimaryColor;
 String _cachedLabel;
@@ -61,5 +59,5 @@ void updateTaskDescription({ String label, Color color }) {
     ..label = label
     ..primaryColor = color?.value ?? 0;
 
-  _activityProxy.ptr.setTaskDescription(description);
+  _activityProxy.setTaskDescription(description);
 }

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

@@ -10,9 +10,7 @@ import 'package:sky_services/flutter/platform/app_messages.mojom.dart' as mojom;
 import 'shell.dart';
 
 mojom.ApplicationMessagesProxy _initHostAppMessagesProxy() {
-  mojom.ApplicationMessagesProxy proxy = new mojom.ApplicationMessagesProxy.unbound();
-  shell.connectToViewAssociatedService(proxy);
-  return proxy;
+  return shell.connectToViewAssociatedService(mojom.ApplicationMessages.connectToService);
 }
 
 final mojom.ApplicationMessagesProxy _hostAppMessagesProxy = _initHostAppMessagesProxy();
@@ -49,7 +47,7 @@ final _ApplicationMessagesImpl _appMessages = new _ApplicationMessagesImpl();
 class HostMessages {
   /// Send a message to the host application.
   static Future<String> sendToHost(String messageName, String message) async {
-    return (await _hostAppMessagesProxy.ptr.sendString(messageName, message)).reply;
+    return (await _hostAppMessagesProxy.sendString(messageName, message)).reply;
   }
 
   /// Register a callback for messages received from the host application.

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

@@ -8,7 +8,7 @@ import 'dart:typed_data';
 
 import 'package:flutter/http.dart' as http;
 import 'package:mojo/core.dart' as core;
-import 'package:mojo_services/mojo/asset_bundle/asset_bundle.mojom.dart';
+import 'package:mojo_services/mojo/asset_bundle/asset_bundle.mojom.dart' as mojom;
 
 import 'image_cache.dart';
 import 'image_decoder.dart';
@@ -122,29 +122,29 @@ abstract class CachingAssetBundle extends AssetBundle {
 
 /// An [AssetBundle] that loads resources from a Mojo service.
 class MojoAssetBundle extends CachingAssetBundle {
-  /// Creates an [AssetBundle] interface around the given [AssetBundleProxy] Mojo service.
+  /// Creates an [AssetBundle] interface around the given [mojom.AssetBundleProxy] Mojo service.
   MojoAssetBundle(this._bundle);
 
   /// Retrieves the asset bundle located at the given URL, unpacks it, and provides it contents.
   factory MojoAssetBundle.fromNetwork(String relativeUrl) {
-    AssetBundleProxy bundle = new AssetBundleProxy.unbound();
+    mojom.AssetBundleProxy bundle = new mojom.AssetBundleProxy.unbound();
     _fetchAndUnpackBundle(relativeUrl, bundle);
     return new MojoAssetBundle(bundle);
   }
 
-  static Future<Null> _fetchAndUnpackBundle(String relativeUrl, AssetBundleProxy bundle) async {
+  static Future<Null> _fetchAndUnpackBundle(String relativeUrl, mojom.AssetBundleProxy bundle) async {
     core.MojoDataPipeConsumer bundleData = await http.readDataPipe(Uri.base.resolve(relativeUrl));
-    AssetUnpackerProxy unpacker = new AssetUnpackerProxy.unbound();
-    shell.connectToService("mojo:asset_bundle", unpacker);
-    unpacker.ptr.unpackZipStream(bundleData, bundle);
+    mojom.AssetUnpackerProxy unpacker = shell.connectToApplicationService(
+      'mojo:asset_bundle', mojom.AssetUnpacker.connectToService);
+    unpacker.unpackZipStream(bundleData, bundle);
     unpacker.close();
   }
 
-  AssetBundleProxy _bundle;
+  mojom.AssetBundleProxy _bundle;
 
   @override
   Future<core.MojoDataPipeConsumer> load(String key) async {
-    return (await _bundle.ptr.getAsStream(key)).assetData;
+    return (await _bundle.getAsStream(key)).assetData;
   }
 }
 
@@ -153,7 +153,7 @@ AssetBundle _initRootBundle() {
   if (h == core.MojoHandle.INVALID)
     return new NetworkAssetBundle(Uri.base);
   core.MojoHandle handle = new core.MojoHandle(h);
-  return new MojoAssetBundle(new AssetBundleProxy.fromHandle(handle));
+  return new MojoAssetBundle(new mojom.AssetBundleProxy.fromHandle(handle));
 }
 
 /// The [AssetBundle] from which this application was loaded.

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

@@ -11,9 +11,7 @@ import 'shell.dart';
 export 'package:sky_services/editing/editing.mojom.dart' show ClipboardData;
 
 mojom.ClipboardProxy _initClipboardProxy() {
-  mojom.ClipboardProxy proxy = new mojom.ClipboardProxy.unbound();
-  shell.connectToService('mojo:clipboard', proxy);
-  return proxy;
+  return shell.connectToApplicationService('mojo:clipboard', mojom.Clipboard.connectToService);
 }
 
 final mojom.ClipboardProxy _clipboardProxy = _initClipboardProxy();
@@ -26,10 +24,10 @@ class Clipboard {
   Clipboard._();
 
   static void setClipboardData(mojom.ClipboardData clip) {
-    _clipboardProxy.ptr.setClipboardData(clip);
+    _clipboardProxy.setClipboardData(clip);
   }
 
   static Future<mojom.ClipboardData> getClipboardData(String format) async {
-    return (await _clipboardProxy.ptr.getClipboardData(format)).clip;
+    return (await _clipboardProxy.getClipboardData(format)).clip;
   }
 }

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

@@ -9,9 +9,7 @@ import 'package:sky_services/flutter/platform/haptic_feedback.mojom.dart' as moj
 import 'shell.dart';
 
 mojom.HapticFeedbackProxy _initHapticFeedbackProxy() {
-  mojom.HapticFeedbackProxy proxy = new mojom.HapticFeedbackProxy.unbound();
-  shell.connectToService('mojo:flutter_platform', proxy);
-  return proxy;
+  return shell.connectToApplicationService('mojo:flutter_platform', mojom.HapticFeedback.connectToService);
 }
 
 final mojom.HapticFeedbackProxy _hapticFeedbackProxy = _initHapticFeedbackProxy();
@@ -39,6 +37,6 @@ class HapticFeedback {
   ///   feedback if the device does not have a vibrator or one is disabled in
   ///   system settings.
   static Future<bool> vibrate() async {
-    return (await _hapticFeedbackProxy.ptr.vibrate()).success;
+    return (await _hapticFeedbackProxy.vibrate()).success;
   }
 }

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

@@ -83,10 +83,8 @@ class KeyboardHandle {
 }
 
 mojom.KeyboardProxy _initKeyboardProxy() {
-  mojom.KeyboardProxy proxy = new mojom.KeyboardProxy.unbound();
-  shell.connectToViewAssociatedService(proxy);
-  return proxy;
+  return shell.connectToViewAssociatedService(mojom.Keyboard.connectToService);
 }
 
 final mojom.KeyboardProxy _keyboardProxy = _initKeyboardProxy();
-final Keyboard keyboard = new Keyboard(_keyboardProxy.ptr);
+final Keyboard keyboard = new Keyboard(_keyboardProxy);

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

@@ -10,9 +10,7 @@ import 'package:sky_services/flutter/platform/path_provider.mojom.dart' as mojom
 import 'shell.dart';
 
 mojom.PathProviderProxy _initPathProviderProxy() {
-  mojom.PathProviderProxy proxy = new mojom.PathProviderProxy.unbound();
-  shell.connectToService('mojo:flutter_platform', proxy);
-  return proxy;
+  return shell.connectToApplicationService('mojo:flutter_platform', mojom.PathProvider.connectToService);
 }
 
 final mojom.PathProviderProxy _pathProviderProxy = _initPathProviderProxy();
@@ -32,7 +30,7 @@ class PathProvider {
   ///  * _iOS_: `NSTemporaryDirectory()`
   ///  * _Android_: `getCacheDir()` on the context.
   static Future<Directory> getTemporaryDirectory() async {
-    return new Directory((await _pathProviderProxy.ptr.temporaryDirectory()).path);
+    return new Directory((await _pathProviderProxy.temporaryDirectory()).path);
   }
 
   /// Path to a directory where the application may place files that are private
@@ -44,6 +42,6 @@ class PathProvider {
   ///  * _iOS_: `NSDocumentsDirectory`
   ///  * _Android_: The AppData directory.
   static Future<Directory> getApplicationDocumentsDirectory() async {
-    return new Directory((await _pathProviderProxy.ptr.applicationDocumentsDirectory()).path);
+    return new Directory((await _pathProviderProxy.applicationDocumentsDirectory()).path);
   }
 }

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

@@ -10,10 +10,80 @@ import 'package:mojo/core.dart' as core;
 import 'package:mojo/mojo/service_provider.mojom.dart' as mojom;
 import 'package:mojo/mojo/shell.mojom.dart' as mojom;
 
-/// Signature for replacements for [shell.connectToService]. Implementations
-/// should return true if they handled the request, or false if the request
-/// should fall through to the default requestService.
-typedef bool OverrideConnectToService(String url, Object proxy);
+/// Signature for connecting to services. The generated mojom.dart code has
+/// static functions that match this signature on the interface objects. For
+/// example, the `mojom.Foo` interface has a `mojom.Foo.connectToService`
+/// function that matches this signature.
+typedef bindings.Proxy<dynamic> ServiceConnectionCallback(
+    bindings.ServiceConnector s, String url, [String serviceName]);
+
+/// Signature for replacements for [shell.connectToApplicationService]. If the
+/// function returns `null`, then [shell.connectToApplicationService] will fall
+/// back to its default behavior.
+typedef bindings.Proxy<dynamic> OverrideConnectToService(String url, ServiceConnectionCallback callback);
+
+ApplicationConnection _initEmbedderConnection() {
+  core.MojoHandle incomingServicesHandle = new core.MojoHandle(ui.MojoServices.takeIncomingServices());
+  core.MojoHandle outgoingServicesHandle = new core.MojoHandle(ui.MojoServices.takeOutgoingServices());
+  if (!incomingServicesHandle.isValid || !outgoingServicesHandle.isValid)
+    return null;
+  mojom.ServiceProviderProxy incomingServices = new mojom.ServiceProviderProxy.fromHandle(incomingServicesHandle);
+  mojom.ServiceProviderStub outgoingServices = new mojom.ServiceProviderStub.fromHandle(outgoingServicesHandle);
+  return new ApplicationConnection(outgoingServices, incomingServices);
+}
+
+mojom.ShellProxy _takeShell() {
+  core.MojoHandle shellHandle = new core.MojoHandle(ui.MojoServices.takeShell());
+  if (!shellHandle.isValid)
+    return null;
+  return new mojom.ShellProxy.fromHandle(shellHandle);
+}
+
+mojom.ServiceProviderProxy _takeViewServices() {
+  core.MojoHandle services = new core.MojoHandle(ui.MojoServices.takeViewServices());
+  if (!services.isValid)
+    return null;
+  return new mojom.ServiceProviderProxy.fromHandle(services);
+}
+
+class _ShellServiceConnector extends bindings.ServiceConnector {
+  @override
+  void connectToService(String url, bindings.Proxy<dynamic> proxy, [String serviceName]) {
+    final MojoShell instance = MojoShell.instance;
+    if (url == null || instance._shell == null) {
+      // If the application URL is null, it means the service to connect
+      // to is one provided by the embedder.
+      // If the applircation URL isn't null but there's no shell, then
+      // ask the embedder in case it provides it. (For example, if you're
+      // running on Android without the Mojo shell, then you can obtain
+      // the media service from the embedder directly, instead of having
+      // to ask the media application for it.)
+      // This makes it easier to write an application that works both
+      // with and without a Mojo environment.
+      instance._embedderConnection?.requestService(proxy);
+      return;
+    }
+    mojom.ServiceProviderProxy services = new mojom.ServiceProviderProxy.unbound();
+    instance._shell.connectToApplication(url, services, null);
+    core.MojoMessagePipe pipe = new core.MojoMessagePipe();
+    proxy.ctrl.bind(pipe.endpoints[0]);
+    services.connectToService_(serviceName, pipe.endpoints[1]);
+    services.close();
+  }
+}
+
+class _ViewAssociatedServiceConnector extends bindings.ServiceConnector {
+  final mojom.ServiceProviderProxy _viewServices = _takeViewServices();
+
+  @override
+  void connectToService(String url, bindings.Proxy<dynamic> proxy, [String serviceName]) {
+    if (_viewServices != null) {
+      core.MojoMessagePipe pipe = new core.MojoMessagePipe();
+      proxy.ctrl.bind(pipe.endpoints[0]);
+      _viewServices.connectToService_(serviceName, pipe.endpoints[1]);
+    }
+  }
+}
 
 /// Manages connections with embedder-provided services.
 class MojoShell {
@@ -30,24 +100,11 @@ class MojoShell {
   static MojoShell get instance => _instance;
   static MojoShell _instance;
 
-  static mojom.ShellProxy _initShellProxy() {
-    core.MojoHandle shellHandle = new core.MojoHandle(ui.MojoServices.takeShell());
-    if (!shellHandle.isValid)
-      return null;
-    return new mojom.ShellProxy.fromHandle(shellHandle);
-  }
-  final mojom.Shell _shell = _initShellProxy()?.ptr;
-
-  static ApplicationConnection _initEmbedderConnection() {
-    core.MojoHandle incomingServicesHandle = new core.MojoHandle(ui.MojoServices.takeIncomingServices());
-    core.MojoHandle outgoingServicesHandle = new core.MojoHandle(ui.MojoServices.takeOutgoingServices());
-    if (!incomingServicesHandle.isValid || !outgoingServicesHandle.isValid)
-      return null;
-    mojom.ServiceProviderProxy incomingServices = new mojom.ServiceProviderProxy.fromHandle(incomingServicesHandle);
-    mojom.ServiceProviderStub outgoingServices = new mojom.ServiceProviderStub.fromHandle(outgoingServicesHandle);
-    return new ApplicationConnection(outgoingServices, incomingServices);
-  }
   final ApplicationConnection _embedderConnection = _initEmbedderConnection();
+  final mojom.Shell _shell = _takeShell();
+
+  final _ShellServiceConnector _shellServiceConnector = new _ShellServiceConnector();
+  final _ViewAssociatedServiceConnector _viewServiceConnector = new _ViewAssociatedServiceConnector();
 
   /// Whether [connectToApplication] is able to connect to other applications.
   bool get canConnectToOtherApplications => _shell != null;
@@ -83,46 +140,21 @@ class MojoShell {
   /// and then invoke the method `bar()` on it:
   ///
   /// ```dart
-  /// mojom.FooProxy foo = new mojom.FooProxy.unbound();
-  /// shell.connectToService("mojo:foo", foo);
-  /// foo.ptr.bar();
+  /// mojom.FooProxy foo = shell.connectToApplicationService(
+  ///    "mojo:foo", mojom.Foo.connectToService);
+  /// foo.bar();
   /// ```
   ///
   /// For examples of mojom files, see the `sky_services` package.
   ///
   /// See also [connectToViewAssociatedService].
-  void connectToService(String url, bindings.ProxyBase proxy) {
-    if (overrideConnectToService != null && overrideConnectToService(url, proxy))
-      return;
-    if (url == null || _shell == null) {
-      // If the application URL is null, it means the service to connect
-      // to is one provided by the embedder.
-      // If the applircation URL isn't null but there's no shell, then
-      // ask the embedder in case it provides it. (For example, if you're
-      // running on Android without the Mojo shell, then you can obtain
-      // the media service from the embedder directly, instead of having
-      // to ask the media application for it.)
-      // This makes it easier to write an application that works both
-      // with and without a Mojo environment.
-      _embedderConnection?.requestService(proxy);
-      return;
-    }
-    mojom.ServiceProviderProxy services = new mojom.ServiceProviderProxy.unbound();
-    _shell.connectToApplication(url, services, null);
-    core.MojoMessagePipe pipe = new core.MojoMessagePipe();
-    proxy.impl.bind(pipe.endpoints[0]);
-    services.ptr.connectToService(proxy.serviceName, pipe.endpoints[1]);
-    services.close();
+  bindings.Proxy<dynamic> connectToApplicationService(String url, ServiceConnectionCallback callback) {
+    bindings.Proxy<dynamic> proxy;
+    if (overrideConnectToService != null)
+      proxy = overrideConnectToService(url, callback);
+    return proxy ?? callback(_shellServiceConnector, url);
   }
 
-  static mojom.ServiceProviderProxy _takeViewServices() {
-    core.MojoHandle services = new core.MojoHandle(ui.MojoServices.takeViewServices());
-    if (!services.isValid)
-      return null;
-    return new mojom.ServiceProviderProxy.fromHandle(services);
-  }
-  final mojom.ServiceProviderProxy _viewServices = _takeViewServices();
-
   /// Attempts to connect to a service provided specifically for the current
   /// view by the embedder or host platform.
   ///
@@ -136,26 +168,23 @@ class MojoShell {
   /// `bar()` on it:
   ///
   /// ```dart
-  /// mojom.FooProxy foo = new mojom.FooProxy.unbound();
-  /// shell.connectToViewAssociatedService(foo);
-  /// foo.ptr.bar();
+  /// mojom.FooProxy foo = shell.connectToViewAssociatedService(
+  ///   mojom.Foo.connectToService);
+  /// foo.bar();
   /// ```
   ///
   /// For examples of mojom files, see the `sky_services` package.
   ///
   /// See also [connectToService].
-  void connectToViewAssociatedService(bindings.ProxyBase proxy) {
-    if (overrideConnectToService != null && overrideConnectToService(null, proxy))
-      return;
-    if (_viewServices == null)
-      return;
-    core.MojoMessagePipe pipe = new core.MojoMessagePipe();
-    proxy.impl.bind(pipe.endpoints[0]);
-    _viewServices.ptr.connectToService(proxy.serviceName, pipe.endpoints[1]);
+  bindings.Proxy<dynamic> connectToViewAssociatedService(ServiceConnectionCallback callback) {
+    bindings.Proxy<dynamic> proxy;
+    if (overrideConnectToService != null)
+      proxy = overrideConnectToService(null, callback);
+    return proxy ?? callback(_viewServiceConnector, null);
   }
 
   /// Registers a service to expose to the embedder.
-  /// 
+  ///
   /// For example, suppose a Flutter application wanted to provide a service
   /// `Foo` to the embedder, that a mojom file declaring `Foo` was imported with
   /// the prefix `mojom`, that `package:mojo/core.dart` was imported with the
@@ -163,7 +192,7 @@ class MojoShell {
   /// the class `MyFooImplementation`. The following code, run during the
   /// binding initialization (i.e. during the same call stack as the call to the
   /// [new MojoShell] constructor) would achieve this:
-  /// 
+  ///
   /// ```dart
   /// shell.provideService(mojom.Foo.serviceName, (core.MojoMessagePipeEndpoint endpoint) {
   ///   mojom.FooStub foo = new mojom.FooStub.fromEndpoint(endpoint);

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

@@ -12,9 +12,7 @@ import 'shell.dart';
 export 'package:sky_services/flutter/platform/system_chrome.mojom.dart' show DeviceOrientation;
 
 mojom.SystemChromeProxy _initSystemChromeProxy() {
-  mojom.SystemChromeProxy proxy = new mojom.SystemChromeProxy.unbound();
-  shell.connectToService('mojo:flutter_platform', proxy);
-  return proxy;
+  return shell.connectToApplicationService('mojo:flutter_platform', mojom.SystemChrome.connectToService);
 }
 
 final mojom.SystemChromeProxy _systemChromeProxy = _initSystemChromeProxy();
@@ -36,7 +34,7 @@ class SystemChrome {
   ///   boolean indicating if the orientation mask is valid and the changes
   ///   could be conveyed successfully to the embedder.
   static Future<bool> setPreferredOrientations(int deviceOrientationMask) async {
-    return (await _systemChromeProxy.ptr.setPreferredOrientations(deviceOrientationMask)).success;
+    return (await _systemChromeProxy.setPreferredOrientations(deviceOrientationMask)).success;
   }
 
   /// Specifies the set of overlays visible on the embedder when the
@@ -58,6 +56,6 @@ class SystemChrome {
   ///   If the overlay is unsupported on the platform, enabling or disabling
   ///   that overlay is a no-op and always return true.
   static Future<bool> setEnabledSystemUIOverlays(int overlaysMask) async {
-    return (await _systemChromeProxy.ptr.setEnabledSystemUiOverlays(overlaysMask)).success;
+    return (await _systemChromeProxy.setEnabledSystemUiOverlays(overlaysMask)).success;
   }
 }

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

@@ -12,9 +12,7 @@ import 'shell.dart';
 export 'package:sky_services/flutter/platform/system_sound.mojom.dart' show SystemSoundType;
 
 mojom.SystemSoundProxy _initSystemSoundProxy() {
-  mojom.SystemSoundProxy proxy = new mojom.SystemSoundProxy.unbound();
-  shell.connectToService('mojo:flutter_platform', proxy);
-  return proxy;
+  return shell.connectToApplicationService('mojo:flutter_platform', mojom.SystemSound.connectToService);
 }
 
 final mojom.SystemSoundProxy _systemChromeProxy = _initSystemSoundProxy();
@@ -33,6 +31,6 @@ class SystemSound {
   ///   successfully conveyed to the embedder. No sound may actually play if the
   ///   device is muted or the sound was not available on the platform.
   static Future<bool> play(SystemSoundType type) async {
-    return (await _systemChromeProxy.ptr.play(type)).success;
+    return (await _systemChromeProxy.play(type)).success;
   }
 }

packages/flutter/lib/src/widgets/raw_keyboard_listener.dart

@@ -61,9 +61,8 @@ class _RawKeyboardListenerState extends State<RawKeyboardListener> implements mo
     if (_stub != null)
       return;
     _stub = new mojom.RawKeyboardListenerStub.unbound()..impl = this;
-    mojom.RawKeyboardServiceProxy keyboard = new mojom.RawKeyboardServiceProxy.unbound();
-    shell.connectToViewAssociatedService(keyboard);
-    keyboard.ptr.addListener(_stub);
+    mojom.RawKeyboardServiceProxy keyboard = shell.connectToViewAssociatedService(mojom.RawKeyboardService.connectToService);
+    keyboard.addListener(_stub);
     keyboard.close();
   }
 

packages/flutter/test/widget/form_test.dart

@@ -6,7 +6,9 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';
 import 'package:sky_services/editing/editing.mojom.dart' as mojom;
 
-class MockKeyboard implements mojom.Keyboard {
+class MockKeyboard extends mojom.KeyboardProxy {
+  MockKeyboard() : super.unbound();
+
   mojom.KeyboardClient client;
 
   @override
@@ -28,7 +30,7 @@ void main() {
   MockKeyboard mockKeyboard = new MockKeyboard();
 
   setUpAll(() {
-    serviceMocker.registerMockService(mojom.Keyboard.serviceName, mockKeyboard);
+    serviceMocker.registerMockService(mockKeyboard);
   });
 
   void enterText(String testValue) {

packages/flutter/test/widget/input_test.dart

@@ -7,7 +7,9 @@ import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:sky_services/editing/editing.mojom.dart' as mojom;
 
-class MockKeyboard implements mojom.Keyboard {
+class MockKeyboard extends mojom.KeyboardProxy {
+  MockKeyboard() : super.unbound();
+
   mojom.KeyboardClient client;
 
   @override
@@ -25,7 +27,9 @@ class MockKeyboard implements mojom.Keyboard {
   void setEditingState(mojom.EditingState state) {}
 }
 
-class MockClipboard implements mojom.Clipboard {
+class MockClipboard extends mojom.ClipboardProxy {
+  MockClipboard() : super.unbound();
+
   mojom.ClipboardData _clip;
 
   @override
@@ -41,9 +45,9 @@ class MockClipboard implements mojom.Clipboard {
 
 void main() {
   MockKeyboard mockKeyboard = new MockKeyboard();
-  serviceMocker.registerMockService(mojom.Keyboard.serviceName, mockKeyboard);
+  serviceMocker.registerMockService(mockKeyboard);
   MockClipboard mockClipboard = new MockClipboard();
-  serviceMocker.registerMockService(mojom.Clipboard.serviceName, mockClipboard);
+  serviceMocker.registerMockService(mockClipboard);
 
   void enterText(String testValue) {
     // Simulate entry of text through the keyboard.

packages/flutter_sprites/lib/src/sound.dart

@@ -39,7 +39,7 @@ class SoundEffectStream {
 
   /// Stop the sound effect.
   void stop() {
-    _soundPool.ptr.stop(_streamId);
+    _soundPool.stop(_streamId);
   }
 
   /// True if the sound effect is paused.
@@ -48,9 +48,9 @@ class SoundEffectStream {
   set paused(bool value) {
     _paused = value;
     if (_paused) {
-      _soundPool.ptr.pause(_streamId);
+      _soundPool.pause(_streamId);
     } else {
-      _soundPool.ptr.resume(_streamId);
+      _soundPool.resume(_streamId);
     }
   }
 
@@ -59,7 +59,7 @@ class SoundEffectStream {
   double _leftVolume;
   set leftVolume(double value) {
     _leftVolume = value;
-    _soundPool.ptr.setVolume(_streamId, <double>[_leftVolume, _rightVolume]);
+    _soundPool.setVolume(_streamId, <double>[_leftVolume, _rightVolume]);
   }
 
   /// Right volume of the sound effect, valid values are 0.0 to 1.0.
@@ -67,7 +67,7 @@ class SoundEffectStream {
   double _rightVolume;
   set rightVolume(double value) {
     _rightVolume = value;
-    _soundPool.ptr.setVolume(_streamId, <double>[_leftVolume, _rightVolume]);
+    _soundPool.setVolume(_streamId, <double>[_leftVolume, _rightVolume]);
   }
 
   /// The pitch of the sound effect, a value of 1.0 plays back the sound effect
@@ -76,7 +76,7 @@ class SoundEffectStream {
   double _pitch;
   set pitch(double value) {
     _pitch = value;
-    _soundPool.ptr.setRate(_streamId, _pitch);
+    _soundPool.setRate(_streamId, _pitch);
   }
 }
 
@@ -86,10 +86,11 @@ class SoundEffectPlayer {
   /// Creates a new SoundEffectPlayer with a max number of simultaneous
   /// streams specified.
   SoundEffectPlayer(int maxStreams) {
-    MediaServiceProxy mediaService = new MediaServiceProxy.unbound();
-    shell.connectToService("mojo:media_service", mediaService);
+    MediaServiceProxy mediaService = shell.connectToApplicationService(
+      'mojo:media_service', MediaService.connectToService
+    );
     _soundPool = new SoundPoolProxy.unbound();
-    mediaService.ptr.createSoundPool(_soundPool, maxStreams);
+    mediaService.createSoundPool(_soundPool, maxStreams);
   }
 
   SoundPoolProxy _soundPool;
@@ -98,7 +99,7 @@ class SoundEffectPlayer {
 
   /// Loads a sound effect.
   Future<SoundEffect> load(MojoDataPipeConsumer data) async {
-    SoundPoolLoadResponseParams result = await _soundPool.ptr.load(data);
+    SoundPoolLoadResponseParams result = await _soundPool.load(data);
     if (result.success)
       return new SoundEffect(result.soundId);
 
@@ -113,7 +114,7 @@ class SoundEffectPlayer {
     double pitch: 1.0
   }) async {
     int streamId = _nextStreamId++;
-    SoundPoolPlayResponseParams result = await _soundPool.ptr.play(
+    SoundPoolPlayResponseParams result = await _soundPool.play(
       sound._soundId, streamId, <double>[leftVolume, rightVolume], loop, pitch
     );
 
@@ -134,9 +135,9 @@ class SoundEffectPlayer {
   set paused(bool value) {
     _paused = value;
     if (_paused) {
-      _soundPool.ptr.pauseAll();
+      _soundPool.pauseAll();
     } else {
-      _soundPool.ptr.resumeAll();
+      _soundPool.resumeAll();
     }
   }
 }
@@ -180,8 +181,9 @@ class SoundTrackPlayer {
   /// Creates a new [SoundTrackPlayer], typically you will want to use the
   /// [sharedInstance] method to receive the player.
   SoundTrackPlayer() {
-    _mediaService = new MediaServiceProxy.unbound();
-    shell.connectToService("mojo:media_service", _mediaService);
+    _mediaService = shell.connectToApplicationService(
+      'mojo:media_service', MediaService.connectToService
+    );
   }
 
   MediaServiceProxy _mediaService;
@@ -199,9 +201,9 @@ class SoundTrackPlayer {
     // Create media player
     SoundTrack soundTrack = new SoundTrack();
     soundTrack._player = new MediaPlayerProxy.unbound();
-    _mediaService.ptr.createPlayer(soundTrack._player);
+    _mediaService.createPlayer(soundTrack._player);
 
-    await soundTrack._player.ptr.prepare(await pipe);
+    await soundTrack._player.prepare(await pipe);
     return soundTrack;
   }
 
@@ -217,28 +219,29 @@ class SoundTrackPlayer {
     double volume: 1.0,
     double startTime: 0.0
   }) {
-    soundTrack._player.ptr.setLooping(loop);
-    soundTrack._player.ptr.setVolume(volume);
-    soundTrack._player.ptr.seekTo((startTime * 1000.0).toInt());
-    soundTrack._player.ptr.start();
+    soundTrack._player
+      ..setLooping(loop)
+      ..setVolume(volume)
+      ..seekTo((startTime * 1000.0).toInt())
+      ..start();
     _soundTracks.add(soundTrack);
   }
 
   /// Stops a [SoundTrack]. You may also want to call the [unload] method to
   /// remove if from memory if you are not planning to play it again.
   void stop(SoundTrack track) {
-    track._player.ptr.pause();
+    track._player.pause();
   }
 
   /// Pauses all [SoundTrack]s that are currently playing.
   void pauseAll() {
     for (SoundTrack soundTrack in _soundTracks)
-      soundTrack._player.ptr.pause();
+      soundTrack._player.pause();
   }
 
   /// Resumes all [SoundTrack]s that have been loaded by this player.
   void resumeAll() {
     for (SoundTrack soundTrack in _soundTracks)
-      soundTrack._player.ptr.start();
+      soundTrack._player.start();
   }
 }

packages/flutter_test/lib/src/service_mocker.dart

@@ -7,6 +7,15 @@ import 'package:mojo/bindings.dart' as bindings;
 
 import 'binding.dart';
 
+class _MockServiceConnector extends bindings.ServiceConnector {
+  String serviceName;
+
+  @override
+  void connectToService(String url, bindings.Proxy<dynamic> proxy, [String serviceName]) {
+    this.serviceName = serviceName;
+  }
+}
+
 /// Tests can use [ServiceMocker] to register replacement implementations
 /// of Mojo services.
 class ServiceMocker {
@@ -16,23 +25,18 @@ class ServiceMocker {
   }
 
   // Map of interface names to mock implementations.
-  Map<String, Object> _interfaceMocks = <String, Object>{};
-
-  bool _connectToService(String url, bindings.ProxyBase proxy) {
-    Object mock = _interfaceMocks[proxy.serviceName];
-    if (mock != null) {
-      // Replace the proxy's implementation of the service interface with the
-      // mock. The mojom bindings put the "ptr" field on all proxies.
-      (proxy as dynamic).ptr = mock;
-      return true;
-    } else {
-      return false;
-    }
+  Map<String, bindings.Proxy<dynamic>> _interfaceMocks = <String, bindings.Proxy<dynamic>>{};
+
+  bindings.Proxy<dynamic> _connectToService(String url, ServiceConnectionCallback callback) {
+    // TODO(abarth): This is quite awkward. See <https://github.com/domokit/mojo/issues/786>.
+    _MockServiceConnector connector = new _MockServiceConnector();
+    callback(connector, url);
+    return _interfaceMocks[connector.serviceName];
   }
 
   /// Provide a mock implementation for a Mojo interface.
-  void registerMockService(String interfaceName, Object mock) {
-    _interfaceMocks[interfaceName] = mock;
+  void registerMockService(bindings.Proxy<dynamic> mock) {
+    _interfaceMocks[mock.ctrl.serviceName] = mock;
   }
 }