Oilpan: avoid using WeakPtr<> for heap residing objects.

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 108 matching lines @@
 private:
 #if !ENABLE(OILPAN)
     virtual void refFormAssociatedElement() = 0;
     virtual void derefFormAssociatedElement() = 0;
 #endif
 
     void setFormAttributeTargetObserver(PassOwnPtrWillBeRawPtr<FormAttributeTargetObserver>);
     void resetFormAttributeTargetObserver();
 
     OwnPtrWillBeMember<FormAttributeTargetObserver> m_formAttributeTargetObserver;
-#if ENABLE(OILPAN)
-    Member<HTMLFormElement> m_form;
-#else
-    WeakPtr<HTMLFormElement> m_form;
-#endif
+    WeakPtrWillBeMember<HTMLFormElement> m_form;
     OwnPtrWillBeMember<ValidityState> m_validityState;
     String m_customValidationMessage;
     // Non-Oilpan: Even if m_formWasSetByParser is true, m_form can be null
     // because parentNode is not a strong reference and |this| and m_form don't
     // die together.
     // Oilpan: If m_formWasSetByParser is true, m_form is always non-null.
     bool m_formWasSetByParser;
 };
 
 HTMLElement* toHTMLElement(FormAssociatedElement*);
 HTMLElement& toHTMLElement(FormAssociatedElement&);
 const HTMLElement* toHTMLElement(const FormAssociatedElement*);
 const HTMLElement& toHTMLElement(const FormAssociatedElement&);
 
 } // namespace
 
 #endif // FormAssociatedElement_h