Change various helper classes to transition types to get CSSValue entirely onto the gc heap.

Source/core/css/CSSStyleSheet.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010, 2012 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 69 matching lines @@
     CSSRule* item(unsigned index);
 
     virtual void clearOwnerNode() OVERRIDE { didMutate(EntireStyleSheetUpdate); m_ownerNode = 0; }
     virtual CSSRule* ownerRule() const OVERRIDE { return m_ownerRule; }
     virtual KURL baseURL() const OVERRIDE;
     virtual bool isLoading() const OVERRIDE;
 
     void clearOwnerRule() { m_ownerRule = 0; }
     Document* ownerDocument() const;
     MediaQuerySet* mediaQueries() const { return m_mediaQueries.get(); }
-    void setMediaQueries(PassRefPtr<MediaQuerySet>);
+    void setMediaQueries(PassRefPtrWillBeRawPtr<MediaQuerySet>);
     void setTitle(const String& title) { m_title = title; }
 
     class RuleMutationScope {
         WTF_MAKE_NONCOPYABLE(RuleMutationScope);
     public:
         RuleMutationScope(CSSStyleSheet*);
         RuleMutationScope(CSSRule*);
         ~RuleMutationScope();
 
     private:
@@ skipping 23 matching lines @@
     virtual String type() const OVERRIDE { return "text/css"; }
 
     void reattachChildRuleCSSOMWrappers();
 
     bool canAccessRules() const;
 
     RefPtrWillBePersistent<StyleSheetContents> m_contents;
     bool m_isInlineStylesheet;
     bool m_isDisabled;
     String m_title;
-    RefPtr<MediaQuerySet> m_mediaQueries;
+    RefPtrWillBePersistent<MediaQuerySet> m_mediaQueries;
 
     Node* m_ownerNode;
     // FIXME: oilpan: This is a back pointer from CSSImportRule, corresponding
     // to the forward pointer on that, called m_styleSheetCSSOMWrapper. (It is
     // not related to the m_parentStyleSheet pointer which is also typed as
     // CSSStyleSheet, and which is inherited by CSSImportRule from CSSRule).
     // Since m_styleSheetCSSOMWrapper is a RefPtr we know that this object
     // cannot die before the CSSImportRule is destructed, which makes it OK to
     // clear this from ~CSSImportRule. When this is on the GC heap we can make
     // this a regular Member.
     CSSRule* m_ownerRule;
 
     TextPosition m_startPosition;
     bool m_loadCompleted;
 
-    mutable RefPtr<MediaList> m_mediaCSSOMWrapper;
+    mutable RefPtrWillBePersistent<MediaList> m_mediaCSSOMWrapper;
     mutable WillBePersistentHeapVector<RefPtrWillBeMember<CSSRule> > m_childRuleCSSOMWrappers;
     mutable OwnPtr<CSSRuleList> m_ruleListCSSOMWrapper;
 };
 
 inline CSSStyleSheet::RuleMutationScope::RuleMutationScope(CSSStyleSheet* sheet)
     : m_styleSheet(sheet)
 {
     if (m_styleSheet)
         m_styleSheet->willMutateRules();
 }
 
 inline CSSStyleSheet::RuleMutationScope::RuleMutationScope(CSSRule* rule)
     : m_styleSheet(rule ? rule->parentStyleSheet() : 0)
 {
     if (m_styleSheet)
         m_styleSheet->willMutateRules();
 }
 
 inline CSSStyleSheet::RuleMutationScope::~RuleMutationScope()
 {
     if (m_styleSheet)
         m_styleSheet->didMutateRules();
 }
 
 DEFINE_TYPE_CASTS(CSSStyleSheet, StyleSheet, sheet, sheet->isCSSStyleSheet(), sheet.isCSSStyleSheet());
 
 } // namespace
 
 #endif