Dart: Adds Interface and InterfaceRequest interfaces.

mojo/dart/packages/mojo/lib/src/interfaces.dart

Index: mojo/dart/packages/mojo/lib/src/interfaces.dart
diff --git a/mojo/dart/packages/mojo/lib/src/interfaces.dart b/mojo/dart/packages/mojo/lib/src/interfaces.dart
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+// Copyright 2016 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.
+
+part of bindings;
+
+/// [MojoInterface] is the interface implemented by the generated
+/// Interface and InterfaceRequest classes. The [MojoInterfaceControl] field
+/// [ctrl] gives access to the underlying implementation of the interface, which
+/// is either a [ProxyControl] or [StubControl] depending on the situation.
+abstract class MojoInterface<T> {
+  MojoInterfaceControl get ctrl;
+  T impl;
+  Future close({bool immediate: false});
+}
+
+/// This interface is implemented by [ProxyMessageHandler] and
+/// [StubMessageHandler]. Most of the interface is inherited from, and
+/// ultimately implemented by [core.MojoEventHandler].
+abstract class MojoInterfaceControl implements core.MojoEventHandler {
+  String get serviceName;
+  int get version;
+}