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

Source/core/html/FormAssociatedElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 76 matching lines @@
     bool valid() const;
     virtual void setCustomValidity(const String&);
 
     void formAttributeTargetChanged();
 
     typedef WillBeHeapVector<RawPtrWillBeMember<FormAssociatedElement> > List;
 
 protected:
     FormAssociatedElement();
 
-    void trace(Visitor*);
+    virtual void trace(Visitor*);
     void insertedInto(ContainerNode*);
     void removedFrom(ContainerNode*);
     void didMoveToNewDocument(Document& oldDocument);
 
     // FIXME: Remove usage of setForm. resetFormOwner should be enough, and
     // setForm is confusing.
     void setForm(HTMLFormElement*);
     void associateByParser(HTMLFormElement*);
     void formAttributeChanged();
 
@@ skipping 26 matching lines @@
 };
 
 HTMLElement* toHTMLElement(FormAssociatedElement*);
 HTMLElement& toHTMLElement(FormAssociatedElement&);
 const HTMLElement* toHTMLElement(const FormAssociatedElement*);
 const HTMLElement& toHTMLElement(const FormAssociatedElement&);
 
 } // namespace
 
 #endif // FormAssociatedElement_h