Assert that AudioContext::destination() is not called from the audio thread

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 95 matching lines @@
     bool isDestinationInitialized() const
     {
         AudioDestinationNode* dest = destination();
         return dest ? dest->audioDestinationHandler().isInitialized() : false;
     }
 
     // Document notification
     void stop() final;
     bool hasPendingActivity() const final;
 
-    AudioDestinationNode* destination() const { return m_destinationNode.get(); }
+    // Cannnot be called from the audio thread.
+    AudioDestinationNode* destination() const;
 
     size_t currentSampleFrame() const
     {
         return m_destinationNode ? m_destinationNode->audioDestinationHandler().currentSampleFrame() : 0;
     }
 
     double currentTime() const
     {
         return m_destinationNode ? m_destinationNode->audioDestinationHandler().currentTime() : 0;
     }
@@ skipping 220 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