Make RenderObject::style() return a const object

Source/core/rendering/svg/SVGRenderTreeAsText.cpp

 /*
  * Copyright (C) 2004, 2005, 2007, 2009 Apple Inc. All rights reserved.
  *           (C) 2005 Rob Buis <buis@kde.org>
  *           (C) 2006 Alexander Kellett <lypanov@kde.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 615 matching lines @@
     writeResources(ts, shape, indent);
 }
 
 void writeSVGGradientStop(TextStream& ts, const RenderSVGGradientStop& stop, int indent)
 {
     writeStandardPrefix(ts, stop, indent);
 
     SVGStopElement* stopElement = toSVGStopElement(stop.node());
     ASSERT(stopElement);
 
-    RenderStyle* style = stop.style();
+    const RenderStyle* style = stop.style();
     if (!style)
         return;
 
     ts << " [offset=" << stopElement->offset()->currentValue()->value() << "] [color=" << stopElement->stopColorIncludingOpacity() << "]\n";
 }
 
 void writeResources(TextStream& ts, const RenderObject& object, int indent)
 {
     const RenderStyle* style = object.style();
     const SVGRenderStyle& svgStyle = style->svgStyle();
@@ skipping 27 matching lines @@
             ts << " ";
             writeNameAndQuotedValue(ts, "filter", svgStyle.filterResource());
             ts << " ";
             writeStandardPrefix(ts, *filter, 0);
             ts << " " << filter->resourceBoundingBox(&renderer) << "\n";
         }
     }
 }
 
 } // namespace blink