Turn styleWillChange |newStyle| into a reference

Source/core/rendering/RenderLayerModelObject.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010, 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 35 matching lines @@
     explicit RenderLayerModelObject(ContainerNode*);
     virtual ~RenderLayerModelObject();
 
     // This is the only way layers should ever be destroyed.
     void destroyLayer();
 
     bool hasSelfPaintingLayer() const;
     RenderLayer* layer() const { return m_layer.get(); }
     ScrollableArea* scrollableArea() const;
 
-    virtual void styleWillChange(StyleDifference, const RenderStyle* newStyle) OVERRIDE;
+    virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle) OVERRIDE;
     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;
     virtual void updateFromStyle() { }
 
     virtual LayerType layerTypeRequired() const = 0;
 
     // Returns true if the background is painted opaque in the given rect.
     // The query rect is given in local coordinate system.
     virtual bool backgroundIsKnownToBeOpaqueInRect(const LayoutRect&) const { return false; }
 
     // This is null for anonymous renderers.
@@ skipping 17 matching lines @@
 
     // Used to store state between styleWillChange and styleDidChange
     static bool s_wasFloating;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderLayerModelObject, isLayerModelObject());
 
 } // namespace WebCore
 
 #endif // RenderLayerModelObject_h