Have const StyleResolverState return const RenderStyle

Source/core/css/CSSToStyleMap.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.
  * Copyright (C) 2012 Google 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 26 matching lines @@
 class StyleResolverState;
 class NinePieceImage;
 
 // CSSToStyleMap is a short-lived helper object which
 // given the current StyleResolverState can map
 // CSSValue objects into their RenderStyle equivalents.
 
 class CSSToStyleMap {
     WTF_MAKE_NONCOPYABLE(CSSToStyleMap);
 public:
-    // FIXME: This could be const StyleResolverState
-    // except styleImage can include a gradient, which
-    // may resolve a color and may need to flip bits
-    // on StyleResolverState.
     CSSToStyleMap(const StyleResolverState& state, ElementStyleResources& elementStyleResources) : m_state(state), m_elementStyleResources(elementStyleResources) { }
 
     void mapFillAttachment(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillClip(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillComposite(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillBlendMode(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillOrigin(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillImage(CSSPropertyID, FillLayer*, CSSValue*);
     void mapFillRepeatX(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillRepeatY(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillSize(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillXPosition(CSSPropertyID, FillLayer*, CSSValue*) const;
     void mapFillYPosition(CSSPropertyID, FillLayer*, CSSValue*) const;
 
     void mapAnimationDelay(CSSAnimationData*, CSSValue*) const;
     void mapAnimationDirection(CSSAnimationData*, CSSValue*) const;
     void mapAnimationDuration(CSSAnimationData*, CSSValue*) const;
     void mapAnimationFillMode(CSSAnimationData*, CSSValue*) const;
     void mapAnimationIterationCount(CSSAnimationData*, CSSValue*) const;
     void mapAnimationName(CSSAnimationData*, CSSValue*) const;
     void mapAnimationPlayState(CSSAnimationData*, CSSValue*) const;
     void mapAnimationProperty(CSSAnimationData*, CSSValue*) const;
     void mapAnimationTimingFunction(CSSAnimationData*, CSSValue*) const;
 
-    void mapNinePieceImage(CSSPropertyID, CSSValue*, NinePieceImage&);
+    void mapNinePieceImage(RenderStyle* mutableStyle, CSSPropertyID, CSSValue*, NinePieceImage&);
     void mapNinePieceImageSlice(CSSValue*, NinePieceImage&) const;
     LengthBox mapNinePieceImageQuad(CSSValue*) const;
     void mapNinePieceImageRepeat(CSSValue*, NinePieceImage&) const;
 
 private:
-    RenderStyle* style() const;
-    RenderStyle* rootElementStyle() const;
+    const RenderStyle* style() const;
+    const RenderStyle* rootElementStyle() const;
     bool useSVGZoomRules() const;
 
     PassRefPtr<StyleImage> styleImage(CSSPropertyID, CSSValue*);
 
     // FIXME: Consider passing a StyleResolverState (or ElementResolveState)
     // as an argument instead of caching it on this object.
     const StyleResolverState& m_state;
     ElementStyleResources& m_elementStyleResources;
 };
 
 }
 
 #endif