Prevent audio thread access to finished, non-active AudioNodes.

third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.h

 /*
  * Copyright (C) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 302 matching lines @@
     // Oilpan: This Vector holds connection references. We must call
     // AudioHandler::makeConnection when we add an AudioNode to this, and must
     // call AudioHandler::breakConnection() when we remove an AudioNode from
     // this.
     HeapVector<Member<AudioNode>> m_activeSourceNodes;
 
     // The main thread controls m_activeSourceNodes, all updates and additions
     // are performed by it. When the audio thread marks a source node as finished,
     // the nodes are added to |m_finishedSourceNodes| and scheduled for removal
     // from |m_activeSourceNodes| by the main thread.
-    Vector<UntracedMember<AudioNode>> m_finishedSourceNodes;
+    HashSet<UntracedMember<AudioNode>> m_finishedSourceNodes;
 
     // FIXME(dominicc): Move these to AudioContext because only
     // it creates these Promises.
     // Handle Promises for resume() and suspend()
     void resolvePromisesForResume();
     void resolvePromisesForResumeOnMainThread();
 
     // When the context is going away, reject any pending script promise resolvers.
     virtual void rejectPendingResolvers();
 
@@ skipping 30 matching lines @@
     Member<PeriodicWave> m_periodicWaveTriangle;
 
     // This is considering 32 is large enough for multiple channels audio.
     // It is somewhat arbitrary and could be increased if necessary.
     enum { MaxNumberOfChannels = 32 };
 };
 
 } // namespace blink
 
 #endif // AbstractAudioContext_h