Update AbstractAudioContext::m_activeSourceNodes on the main thread only.

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 126 matching lines @@
     AudioContextState contextState() const { return m_contextState; }
 
     AudioBuffer* createBuffer(unsigned numberOfChannels, size_t numberOfFrames, float sampleRate, ExceptionState&);
 
     // Asynchronous audio file data decoding.
     ScriptPromise decodeAudioData(ScriptState*, DOMArrayBuffer* audioData, AudioBufferCallback* successCallback, AudioBufferCallback* errorCallback, ExceptionState&);
 
     // Handles the promise and callbacks when |decodeAudioData| is finished decoding.
     void handleDecodeAudioData(AudioBuffer*, ScriptPromiseResolver*, AudioBufferCallback* successCallback, AudioBufferCallback* errorCallback);
 
-    AudioListener* listener() { return m_listener.get(); }
+    AudioListener* listener() { return m_listener; }
 
     virtual bool hasRealtimeConstraint() = 0;
 
     // The AudioNode create methods are called on the main thread (from JavaScript).
     AudioBufferSourceNode* createBufferSource(ExceptionState&);
     MediaElementAudioSourceNode* createMediaElementSource(HTMLMediaElement*, ExceptionState&);
     MediaStreamAudioSourceNode* createMediaStreamSource(MediaStream*, ExceptionState&);
     MediaStreamAudioDestinationNode* createMediaStreamDestination(ExceptionState&);
     GainNode* createGain(ExceptionState&);
     BiquadFilterNode* createBiquadFilter(ExceptionState&);
@@ skipping 134 matching lines @@
 private:
     bool m_isCleared;
     void clear();
 
     void throwExceptionForClosedState(ExceptionState&);
 
     // When the context goes away, there might still be some sources which
     // haven't finished playing.  Make sure to release them here.
     void releaseActiveSourceNodes();
 
+    void removeFinishedSourceNodes();
+
     Member<AudioListener> m_listener;
 
     // Only accessed in the audio thread.
     // These raw pointers are safe because AudioSourceNodes in
     // m_activeSourceNodes own them.
     Vector<AudioHandler*> m_finishedSourceHandlers;
 
     // List of source nodes. This is either accessed when the graph lock is
     // held, or on the main thread when the audio thread has finished.
     // 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;
+
     // 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();
 
     // True if we're in the process of resolving promises for resume().  Resolving can take some
     // time and the audio context process loop is very fast, so we don't want to call resolve an
     // excessive number of times.
     bool m_isResolvingResumePromises;
 
     unsigned m_connectionCount;
 
     // Graph locking.
-    bool m_didInitializeContextGraphMutex;
     RefPtr<DeferredTaskHandler> m_deferredTaskHandler;
 
     // The state of the AbstractAudioContext.
     AudioContextState m_contextState;
 
     AsyncAudioDecoder m_audioDecoder;
 
     // When a context is closed, the sample rate is cleared.  But decodeAudioData can be called
     // after the context has been closed and it needs the sample rate.  When the context is closed,
     // the sample rate is saved here.
@@ skipping 12 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