Reduce the number of CachedUAStyles

Source/core/rendering/style/CachedUAStyle.h

  /*
  * Copyright (C) 2013 Google, Inc.
  * 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.
  *
@@ skipping 14 matching lines @@
 #include "core/rendering/style/RenderStyle.h"
 
 namespace WebCore {
 
 // RenderTheme::adjustStyle wants the background and borders
 // as specified by the UA sheets, excluding any author rules.
 // We use this class to cache those values during
 // applyMatchedProperties for later use during adjustRenderStyle.
 class CachedUAStyle {
 public:
-    CachedUAStyle()
-        : hasAppearance(false)
-        , backgroundLayers(BackgroundFillLayer)
-        , backgroundColor(StyleColor::currentColor())
-    { }
+    static PassOwnPtr<CachedUAStyle> create(const RenderStyle* style)
+    {
+        return adoptPtr(new CachedUAStyle(style));
+    }
 
+    bool hasAppearance;
+    BorderData border;
+    FillLayer backgroundLayers;
+    StyleColor backgroundColor;
+
+private:
     explicit CachedUAStyle(const RenderStyle* style)
         : hasAppearance(true)
         , backgroundLayers(BackgroundFillLayer)
         , backgroundColor(StyleColor::currentColor())
     {
         ASSERT(style->hasAppearance());
         border = style->border();
         backgroundLayers = *style->backgroundLayers();
         backgroundColor = style->backgroundColor();
     }
+};
 
-    bool hasAppearance;
-    BorderData border;
-    FillLayer backgroundLayers;
-    StyleColor backgroundColor;
-};
 
 
 } // namespace WebCore
 
 #endif // CachedUAStyle_h