Adding streams to dart:html.

sdk/lib/web_audio/dartium/web_audio_dartium.dart

Index: sdk/lib/web_audio/dartium/web_audio_dartium.dart
diff --git a/sdk/lib/web_audio/dartium/web_audio_dartium.dart b/sdk/lib/web_audio/dartium/web_audio_dartium.dart
index dddf9d1ad60b077614e3f9f748eef4f7c6e7dc28..22e287fc4797c5b4f1f870577e75b19b7d679f76 100644
--- a/sdk/lib/web_audio/dartium/web_audio_dartium.dart
+++ b/sdk/lib/web_audio/dartium/web_audio_dartium.dart
@@ -1,5 +1,6 @@
 library web_audio;
 
+import 'dart:async';
 import 'dart:html';
 import 'dart:nativewrappers';
 // DO NOT EDIT
@@ -221,6 +222,8 @@ class AudioBufferSourceNode extends AudioSourceNode {
 class AudioContext extends EventTarget {
   AudioContext.internal() : super.internal();
 
+  static const EventStreamProvider<Event> completeEvent = const EventStreamProvider<Event>('complete');
+
   ///@docsEditable true
   factory AudioContext() => AudioContext._create();
   static AudioContext _create() native "AudioContext_constructor_Callback";
@@ -394,6 +397,8 @@ class AudioContext extends EventTarget {
   /** @domName AudioContext.startRendering */
   void startRendering() native "AudioContext_startRendering_Callback";
 
+  Stream<Event> get onComplete => completeEvent.forTarget(this);
+
 }
 
 /// @docsEditable true