Turn styleWillChange |newStyle| into a reference

Source/core/rendering/RenderObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 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
@@ skipping 979 matching lines @@
     // layoutDidGetCalled indicates whether this render object was re-laid-out
     // since the last call to setLayoutDidGetCalled(false) on this object.
     bool layoutDidGetCalled() { return m_bitfields.layoutDidGetCalled(); }
     void setLayoutDidGetCalled(bool b) { m_bitfields.setLayoutDidGetCalled(b); }
 
     bool shouldDisableLayoutState() const { return hasColumns() || hasTransform() || hasReflection() || style()->isFlippedBlocksWritingMode(); }
 
 protected:
     inline bool layerCreationAllowedForSubtree() const;
 
-    // Overrides should call the superclass at the end
-    virtual void styleWillChange(StyleDifference, const RenderStyle* newStyle);
-    // Overrides should call the superclass at the start
+    // Overrides should call the superclass at the end. m_style will be 0 the first time
+    // this function will be called.
+    virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle);
+    // Overrides should call the superclass at the start. |oldStyle| will be 0 the first
+    // time this function is called.
     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle);
     void propagateStyleToAnonymousChildren(bool blockChildrenOnly = false);
 
     void drawLineForBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2, BoxSide,
                             Color, EBorderStyle, int adjbw1, int adjbw2, bool antialias = false);
     void drawDashedOrDottedBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2,
         BoxSide, Color, int thickness, EBorderStyle, bool antialias);
     void drawDoubleBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2,
         int length, BoxSide, Color, int thickness, int adjacentWidth1, int adjacentWidth2, bool antialias);
     void drawRidgeOrGrooveBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2,
@@ skipping 405 matching lines @@
 void showTree(const WebCore::RenderObject*);
 void showLineTree(const WebCore::RenderObject*);
 void showRenderTree(const WebCore::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const WebCore::RenderObject* object1, const WebCore::RenderObject* object2);
 
 #endif
 
 #endif // RenderObject_h