Add toSVGCircleElement(), and use it

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 331 matching lines @@
         writeNameValuePair(ts, "y1", element->y1CurrentValue().value(lengthContext));
         writeNameValuePair(ts, "x2", element->x2CurrentValue().value(lengthContext));
         writeNameValuePair(ts, "y2", element->y2CurrentValue().value(lengthContext));
     } else if (svgElement->hasTagName(SVGNames::ellipseTag)) {
         SVGEllipseElement* element = static_cast<SVGEllipseElement*>(svgElement);
         writeNameValuePair(ts, "cx", element->cxCurrentValue().value(lengthContext));
         writeNameValuePair(ts, "cy", element->cyCurrentValue().value(lengthContext));
         writeNameValuePair(ts, "rx", element->rxCurrentValue().value(lengthContext));
         writeNameValuePair(ts, "ry", element->ryCurrentValue().value(lengthContext));
     } else if (svgElement->hasTagName(SVGNames::circleTag)) {
-        SVGCircleElement* element = static_cast<SVGCircleElement*>(svgElement);
+        SVGCircleElement* element = toSVGCircleElement(svgElement);
         writeNameValuePair(ts, "cx", element->cxCurrentValue().value(lengthContext));
         writeNameValuePair(ts, "cy", element->cyCurrentValue().value(lengthContext));
         writeNameValuePair(ts, "r", element->rCurrentValue().value(lengthContext));
     } else if (svgElement->hasTagName(SVGNames::polygonTag) || svgElement->hasTagName(SVGNames::polylineTag)) {
         SVGPolyElement* element = static_cast<SVGPolyElement*>(svgElement);
         writeNameAndQuotedValue(ts, "points", element->pointList().valueAsString());
     } else if (svgElement->hasTagName(SVGNames::pathTag)) {
         SVGPathElement* element = toSVGPathElement(svgElement);
         String pathString;
         // FIXME: We should switch to UnalteredParsing here - this will affect the path dumping output of dozens of tests.
@@ skipping 306 matching lines @@
             ts << " ";
             writeNameAndQuotedValue(ts, "filter", svgStyle->filterResource());
             ts << " ";
             writeStandardPrefix(ts, *filter, 0);
             ts << " " << filter->resourceBoundingBox(&renderer) << "\n";
         }
     }
 }
 
 } // namespace WebCore