Add toSVGCircleElement(), and use it

Source/core/rendering/svg/SVGPathData.cpp

 /*
  * Copyright (C) Research In Motion Limited 2011. 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 18 matching lines @@
 #include "core/svg/SVGPathUtilities.h"
 #include "core/svg/SVGPolygonElement.h"
 #include "core/svg/SVGPolylineElement.h"
 #include "core/svg/SVGRectElement.h"
 #include "wtf/HashMap.h"
 
 namespace WebCore {
 
 static void updatePathFromCircleElement(SVGElement* element, Path& path)
 {
-    ASSERT(element->hasTagName(SVGNames::circleTag));
-    SVGCircleElement* circle = static_cast<SVGCircleElement*>(element);
+    SVGCircleElement* circle = toSVGCircleElement(element);
 
     SVGLengthContext lengthContext(element);
     float r = circle->rCurrentValue().value(lengthContext);
     if (r > 0)
         path.addEllipse(FloatRect(circle->cxCurrentValue().value(lengthContext) - r, circle->cyCurrentValue().value(lengthContext) - r, r * 2, r * 2));
 }
 
 static void updatePathFromEllipseElement(SVGElement* element, Path& path)
 {
     ASSERT(element->hasTagName(SVGNames::ellipseTag));
@@ skipping 104 matching lines @@
         map->set(SVGNames::polygonTag.localName().impl(), updatePathFromPolygonElement);
         map->set(SVGNames::polylineTag.localName().impl(), updatePathFromPolylineElement);
         map->set(SVGNames::rectTag.localName().impl(), updatePathFromRectElement);
     }
 
     if (PathUpdateFunction pathUpdateFunction = map->get(element->localName().impl()))
         (*pathUpdateFunction)(element, path);
 }
 
 } // namespace WebCore