Oilpan: move RenderObjects off heap.

Source/core/dom/FirstLetterPseudoElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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
@@ skipping 25 matching lines @@
 
 class FirstLetterPseudoElement final : public PseudoElement {
     WTF_MAKE_NONCOPYABLE(FirstLetterPseudoElement);
 public:
     static PassRefPtrWillBeRawPtr<FirstLetterPseudoElement> create(Element* parent)
     {
         return adoptRefWillBeNoop(new FirstLetterPseudoElement(parent));
     }
 
     virtual ~FirstLetterPseudoElement();
-    virtual void trace(Visitor*) override;
 
     static RenderObject* firstLetterTextRenderer(const Element&);
     static unsigned firstLetterLength(const String&);
 
     void setRemainingTextRenderer(RenderTextFragment*);
     RenderTextFragment* remainingTextRenderer() const { return m_remainingTextRenderer; }
 
     void updateTextFragments();
 
     virtual void attach(const AttachContext& = AttachContext()) override;
     virtual void detach(const AttachContext& = AttachContext()) override;
 
 private:
     explicit FirstLetterPseudoElement(Element*);
 
     virtual void didRecalcStyle(StyleRecalcChange) override;
 
     void attachFirstLetterTextRenderers();
     RenderStyle* styleForFirstLetter(RenderObject*);
 
-    RawPtrWillBeMember<RenderTextFragment> m_remainingTextRenderer;
+    RenderTextFragment* m_remainingTextRenderer;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(FirstLetterPseudoElement, isFirstLetterPseudoElement());
 
 } // namespace blink
 
 #endif // FirstLetterPseudoElement_h