Reduce the number of CachedUAStyles

Source/core/css/resolver/StyleResolverState.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 82 matching lines @@
 
     void setLineHeightValue(CSSValue* value) { m_lineHeightValue = value; }
     CSSValue* lineHeightValue() { return m_lineHeightValue; }
 
     void cacheUserAgentBorderAndBackground()
     {
         // RenderTheme only needs the cached style if it has an appearance,
         // and constructing it is expensive so we avoid it if possible.
         if (!style()->hasAppearance())
             return;
-        m_cachedUAStyle = CachedUAStyle(style());
+
+        m_cachedUAStyle = CachedUAStyle::create(style());
     }
-    const CachedUAStyle& cachedUAStyle() const { return m_cachedUAStyle; }
+
+    const CachedUAStyle* cachedUAStyle() const
+    {
+        return m_cachedUAStyle.get();
+    }
 
     ElementStyleResources& elementStyleResources() { return m_elementStyleResources; }
     const CSSToStyleMap& styleMap() const { return m_styleMap; }
     CSSToStyleMap& styleMap() { return m_styleMap; }
 
     // FIXME: Once styleImage can be made to not take a StyleResolverState
     // this convenience function should be removed. As-is, without this, call
     // sites are extremely verbose.
     PassRefPtr<StyleImage> styleImage(CSSPropertyID propertyId, CSSValue* value)
     {
@@ skipping 27 matching lines @@
 
     OwnPtrWillBeMember<CSSAnimationUpdate> m_animationUpdate;
 
     bool m_applyPropertyToRegularStyle;
     bool m_applyPropertyToVisitedLinkStyle;
 
     RawPtrWillBeMember<CSSValue> m_lineHeightValue;
 
     FontBuilder m_fontBuilder;
 
-    CachedUAStyle m_cachedUAStyle;
+    OwnPtr<CachedUAStyle> m_cachedUAStyle;
 
     ElementStyleResources m_elementStyleResources;
     // CSSToStyleMap is a pure-logic class and only contains
     // a back-pointer to this object.
     CSSToStyleMap m_styleMap;
     Vector<AtomicString> m_contentAttrValues;
 
     RawPtrWillBeMember<StyleRule> m_currentRule;
 };
 
 } // namespace WebCore
 
 #endif // StyleResolverState_h