Keep AudioScheduledSourceNode alive until onended is called.

Source/modules/webaudio/AudioBufferSourceNode.idl

Index: Source/modules/webaudio/AudioBufferSourceNode.idl
diff --git a/Source/modules/webaudio/AudioBufferSourceNode.idl b/Source/modules/webaudio/AudioBufferSourceNode.idl
index 24c95eb3b2fbd93ce11b8be8c1c9bd05efa5d766..9ce0515835c961f2a5a7c36826bbf05a522a5741 100644
--- a/Source/modules/webaudio/AudioBufferSourceNode.idl
+++ b/Source/modules/webaudio/AudioBufferSourceNode.idl
@@ -24,7 +24,8 @@
 
 // A cached (non-streamed), memory-resident audio source
 [
-    Conditional=WEB_AUDIO
+    Conditional=WEB_AUDIO,
+    ActiveDOMObject
 ] interface AudioBufferSourceNode : AudioSourceNode {
     [CustomSetter, SetterRaisesException] attribute AudioBuffer buffer;
 
@@ -46,7 +47,7 @@
     [MeasureAs=WebAudioStart] void start(double when);
     [MeasureAs=WebAudioStart, ImplementedAs=startGrain] void start(double when, double grainOffset);
     [MeasureAs=WebAudioStart, ImplementedAs=startGrain] void start(double when, double grainOffset, double grainDuration);
-    void stop(double when);
+    [ImplementedAs=stopNote] void stop(double when);
 
     [DeprecateAs=WebAudioLooping, ImplementedAs=loop] attribute boolean looping; // This is an alias for the .loop attribute for backwards compatibility.