Oilpan: Ensure that classes with virtual trace methods always have vtables for their left-most base…

Source/modules/webaudio/AudioListener.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
@@ skipping 68 matching lines @@
     Mutex& listenerLock() { return m_listenerLock; }
     void addPanner(PannerNode*);
     void removePanner(PannerNode*);
 
     // HRTF DB loader
     HRTFDatabaseLoader* hrtfDatabaseLoader() { return m_hrtfDatabaseLoader.get(); }
     void createAndLoadHRTFDatabaseLoader(float);
     bool isHRTFDatabaseLoaded();
     void waitForHRTFDatabaseLoaderThreadCompletion();
 
-    void trace(Visitor*);
+    virtual void trace(Visitor*);
 
 private:
     AudioListener();
 
     void setPosition(const FloatPoint3D&);
     void setOrientation(const FloatPoint3D&);
     void setUpVector(const FloatPoint3D&);
     void setVelocity(const FloatPoint3D&);
 
     void markPannersAsDirty(unsigned);
@@ skipping 10 matching lines @@
     // List for pannerNodes in context. This is updated only in the main thread,
     // and can be referred in audio thread.
     WillBeHeapVector<RawPtrWillBeMember<PannerNode> > m_panners;
     // HRTF DB loader for panner node.
     RefPtr<HRTFDatabaseLoader> m_hrtfDatabaseLoader;
 };
 
 } // namespace blink
 
 #endif // AudioListener_h