Revert of Oilpan: Move CSSStyleDeclaration and subclasses to the heap using transistion types.

Source/core/css/StylePropertySet.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008, 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 220 matching lines @@
 
     void traceAfterDispatch(Visitor*);
 
 private:
     explicit MutableStylePropertySet(CSSParserMode);
     explicit MutableStylePropertySet(const StylePropertySet&);
     MutableStylePropertySet(const CSSProperty* properties, unsigned count);
 
     bool removeShorthandProperty(CSSPropertyID);
     CSSProperty* findCSSPropertyWithID(CSSPropertyID);
-    OwnPtrWillBeMember<PropertySetCSSStyleDeclaration> m_cssomWrapper;
+    OwnPtr<PropertySetCSSStyleDeclaration> m_cssomWrapper;
 
     friend class StylePropertySet;
 
     WillBeHeapVector<CSSProperty, 4> m_propertyVector;
 };
 
 DEFINE_TYPE_CASTS(MutableStylePropertySet, StylePropertySet, set, set->isMutable(), set.isMutable());
 
 inline MutableStylePropertySet* toMutableStylePropertySet(const RefPtr<StylePropertySet>& set)
 {
@@ skipping 42 matching lines @@
 inline int StylePropertySet::findPropertyIndex(CSSPropertyID propertyID) const
 {
     if (m_isMutable)
         return toMutableStylePropertySet(this)->findPropertyIndex(propertyID);
     return toImmutableStylePropertySet(this)->findPropertyIndex(propertyID);
 }
 
 } // namespace WebCore
 
 #endif // StylePropertySet_h