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

Source/core/testing/Internals.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 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.
@@ skipping 287 matching lines @@
 
     void setShouldRevealPassword(Element*, bool, ExceptionState&);
 
     ScriptPromise createResolvedPromise(ScriptState*, ScriptValue);
     ScriptPromise createRejectedPromise(ScriptState*, ScriptValue);
     ScriptPromise addOneToPromise(ScriptState*, ScriptPromise);
     ScriptPromise promiseCheck(ScriptState*, long, bool, const Dictionary&, const String&, const Vector<String>&, ExceptionState&);
     ScriptPromise promiseCheckWithoutExceptionState(ScriptState*, const Dictionary&, const String&, const Vector<String>&);
     ScriptPromise promiseCheckRange(ScriptState*, long);
 
-    void trace(Visitor*);
+    virtual void trace(Visitor*);
 
     void setValueForUser(Element*, const String&);
 
     String textSurroundingNode(Node*, int x, int y, unsigned long maxLength);
 
     void setFocused(bool);
 
     bool ignoreLayoutWithPendingStylesheets(Document*);
 
     void setNetworkStateNotifierTestOnly(bool);
@@ skipping 11 matching lines @@
     PassRefPtrWillBeRawPtr<ClientRectList> annotatedRegions(Document*, bool draggable, ExceptionState&);
 
     DocumentMarker* markerAt(Node*, const String& markerType, unsigned index, ExceptionState&);
     RefPtrWillBeMember<InternalRuntimeFlags> m_runtimeFlags;
     RefPtrWillBeMember<InternalProfilers> m_profilers;
 };
 
 } // namespace blink
 
 #endif