Reduce the number of CachedUAStyles

Source/core/rendering/RenderThemeChromiumMac.h

 /*
  * This file is part of the theme implementation for form controls in WebCore.
  *
  * Copyright (C) 2005 Apple Computer, Inc.
  * Copyright (C) 2008, 2009 Google, Inc.
  *
  * 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 26 matching lines @@
     static PassRefPtr<RenderTheme> create();
 
     // A method asking if the control changes its tint when the window has focus or not.
     virtual bool controlSupportsTints(const RenderObject*) const OVERRIDE;
 
     // A general method asking if any control tinting is supported at all.
     virtual bool supportsControlTints() const OVERRIDE { return true; }
 
     virtual void adjustRepaintRect(const RenderObject*, IntRect&) OVERRIDE;
 
-    virtual bool isControlStyled(const RenderStyle*, const CachedUAStyle&) const OVERRIDE;
+    virtual bool isControlStyled(const RenderStyle*, const CachedUAStyle*) const OVERRIDE;
 
     virtual Color platformActiveSelectionBackgroundColor() const OVERRIDE;
     virtual Color platformInactiveSelectionBackgroundColor() const OVERRIDE;
     virtual Color platformActiveSelectionForegroundColor() const OVERRIDE;
     virtual Color platformActiveListBoxSelectionBackgroundColor() const OVERRIDE;
     virtual Color platformActiveListBoxSelectionForegroundColor() const OVERRIDE;
     virtual Color platformInactiveListBoxSelectionBackgroundColor() const OVERRIDE;
     virtual Color platformInactiveListBoxSelectionForegroundColor() const OVERRIDE;
     virtual Color platformFocusRingColor() const OVERRIDE;
 
@@ skipping 148 matching lines @@
     mutable RetainPtr<NSTextFieldCell> m_textField;
 
     mutable HashMap<int, RGBA32> m_systemColorCache;
 
     RetainPtr<WebCoreRenderThemeNotificationObserver> m_notificationObserver;
 };
 
 } // namespace WebCore
 
 #endif // RenderThemeChromiumMac_h