Make RenderObject::style() return a const object

Source/core/svg/SVGStopElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 40 matching lines @@
         SVGElement::InvalidationGuard invalidationGuard(this);
 
         if (renderer())
             markForLayoutAndParentResourceInvalidation(renderer());
         return;
     }
 
     SVGElement::svgAttributeChanged(attrName);
 }
 
-RenderObject* SVGStopElement::createRenderer(RenderStyle*)
+RenderObject* SVGStopElement::createRenderer(const RenderStyle*)
 {
     return new RenderSVGGradientStop(this);
 }
 
 bool SVGStopElement::rendererIsNeeded(const RenderStyle&)
 {
     return true;
 }
 
 Color SVGStopElement::stopColorIncludingOpacity() const
 {
-    RenderStyle* style = renderer() ? renderer()->style() : 0;
+    const RenderStyle* style = renderer() ? renderer()->style() : 0;

[rune, 2015/01/29 23:16:32]

Does nullptr instead of 0 work here?

[Julien - ping for review, 2015/02/10 07:33:20]

Done.

     // FIXME: This check for null style exists to address Bug WK 90814, a rare crash condition in
     // which the renderer or style is null. This entire class is scheduled for removal (Bug WK 86941)
     // and we will tolerate this null check until then.
     if (!style)
         return Color(Color::transparent); // Transparent black.
 
     const SVGRenderStyle& svgStyle = style->svgStyle();
     return svgStyle.stopColor().combineWithAlpha(svgStyle.stopOpacity());
 }
 
 } // namespace blink