Tried to move AudioSummingJuction to oilpan

Source/modules/webaudio/AudioNodeInput.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 61 matching lines @@
     // Called from context's audio thread.
     AudioBus* bus();
 
     // updateInternalBus() updates m_internalSummingBus appropriately for the number of channels.
     // This must be called when we own the context's graph lock in the audio thread at the very start or end of the render quantum.
     void updateInternalBus();
 
     // The number of channels of the connection with the largest number of channels.
     unsigned numberOfChannels() const;
 
+    virtual void trace(Visitor*) OVERRIDE;
+
 private:
     AudioNode* m_node;
 
     // m_disabledOutputs contains the AudioNodeOutputs which are disabled (will not be processed) by the audio graph rendering.
     // But, from JavaScript's perspective, these outputs are still connected to us.
     // Generally, these represent disabled connections from "notes" which have finished playing but are not yet garbage collected.
     HashSet<AudioNodeOutput*> m_disabledOutputs;
 
     // Called from context's audio thread.
     AudioBus* internalSummingBus();
     void sumAllConnections(AudioBus* summingBus, size_t framesToProcess);
 
     RefPtr<AudioBus> m_internalSummingBus;
 };
 
 } // namespace WebCore
 
 #endif // AudioNodeInput_h