Oilpan: move RenderObjects off heap.

Source/core/rendering/RenderMenuList.h

 /*
  * This file is part of the select element renderer in WebCore.
  *
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 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 19 matching lines @@
 #include "platform/geometry/LayoutRect.h"
 
 namespace blink {
 
 class HTMLSelectElement;
 class RenderText;
 
 class RenderMenuList final : public RenderFlexibleBox, private PopupMenuClient {
 
 public:
-    RenderMenuList(Element*);
+    explicit RenderMenuList(Element*);
     virtual ~RenderMenuList();
     virtual void destroy() override;
-    virtual void trace(Visitor*) override;
 
     bool popupIsVisible() const { return m_popupIsVisible; }
     void showPopup();
     void hidePopup();
     PopupMenu* popup() const { return m_popup.get(); }
 
     void setOptionsChanged(bool changed) { m_optionsChanged = changed; }
 
     void didSetSelectedIndex(int listIndex);
 
@@ skipping 58 matching lines @@
     void getItemBackgroundColor(unsigned listIndex, Color&, bool& itemHasCustomBackgroundColor) const;
 
     void createInnerBlock();
     void adjustInnerStyle();
     void setText(const String&);
     void setTextFromOption(int optionIndex);
     void updateOptionsWidth();
 
     void didUpdateActiveOption(int optionIndex);
 
-    RawPtrWillBeMember<RenderText> m_buttonText;
-    RawPtrWillBeMember<RenderBlock> m_innerBlock;
+    RenderText* m_buttonText;
+    RenderBlock* m_innerBlock;
 
     bool m_optionsChanged;
     int m_optionsWidth;
 
     int m_lastActiveIndex;
 
     RefPtr<RenderStyle> m_optionStyle;
 
-    RefPtrWillBeMember<PopupMenu> m_popup;
+    RefPtrWillBePersistent<PopupMenu> m_popup;
     bool m_popupIsVisible;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderMenuList, isMenuList());
 
 }
 
 #endif