Merge 157615 "Keep AudioScheduledSourceNode alive until onended ..."

Source/modules/webaudio/AudioScheduledSourceNode.h

Index: Source/modules/webaudio/AudioScheduledSourceNode.h
===================================================================
--- Source/modules/webaudio/AudioScheduledSourceNode.h	(revision 157760)
+++ Source/modules/webaudio/AudioScheduledSourceNode.h	(working copy)
@@ -54,6 +54,17 @@
         FINISHED_STATE = 3
     };
 
+    // This helper class handles the lifetime of an AudioScheduledSourceNode with an onended event
+    // listener. This keeps the node alive until the event listener is processed.
+    class NotifyEndedTask {
+    public:
+        NotifyEndedTask(PassRefPtr<AudioScheduledSourceNode> scheduledNode);
+        void notifyEnded();
+
+    private:
+        RefPtr<AudioScheduledSourceNode> m_scheduledNode;
+    };
+
     AudioScheduledSourceNode(AudioContext*, float sampleRate);
 
     // Scheduling.
@@ -87,7 +98,6 @@
     virtual void finish();
 
     static void notifyEndedDispatch(void*);
-    void notifyEnded();
 
     PlaybackState m_playbackState;