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

Source/core/storage/Storage.h

 /*
  * Copyright (C) 2008 Apple 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 46 matching lines @@
 
     String anonymousIndexedGetter(unsigned, ExceptionState&);
     String anonymousNamedGetter(const AtomicString&, ExceptionState&);
     bool anonymousNamedSetter(const AtomicString& name, const AtomicString& value, ExceptionState&);
     bool anonymousIndexedSetter(unsigned, const AtomicString&, ExceptionState&);
     DeleteResult anonymousNamedDeleter(const AtomicString&, ExceptionState&);
     DeleteResult anonymousIndexedDeleter(unsigned, ExceptionState&);
     void namedPropertyEnumerator(Vector<String>&, ExceptionState&);
     bool namedPropertyQuery(const AtomicString&, ExceptionState&);
 
-    void trace(Visitor*);
+    virtual void trace(Visitor*);
 
 private:
     Storage(LocalFrame*, PassOwnPtrWillBeRawPtr<StorageArea>);
 
     OwnPtrWillBeMember<StorageArea> m_storageArea;
 };
 
 } // namespace blink
 
 #endif // Storage_h