Introduce toSVGPatternElement(), 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 509 matching lines @@
         if (marker->angle() == -1)
             ts << "auto" << "]\n";
         else
             ts << marker->angle() << "]\n";
     } else if (resource->resourceType() == PatternResourceType) {
         RenderSVGResourcePattern* pattern = static_cast<RenderSVGResourcePattern*>(resource);
 
         // Dump final results that are used for rendering. No use in asking SVGPatternElement for its patternUnits(), as it may
         // link to other patterns using xlink:href, we need to build the full inheritance chain, aka. collectPatternProperties()
         PatternAttributes attributes;
-        static_cast<SVGPatternElement*>(pattern->node())->collectPatternAttributes(attributes);
+        toSVGPatternElement(pattern->node())->collectPatternAttributes(attributes);
 
         writeNameValuePair(ts, "patternUnits", attributes.patternUnits());
         writeNameValuePair(ts, "patternContentUnits", attributes.patternContentUnits());
 
         AffineTransform transform = attributes.patternTransform();
         if (!transform.isIdentity())
             ts << " [patternTransform=" << transform << "]";
         ts << "\n";
     } else if (resource->resourceType() == LinearGradientResourceType) {
         RenderSVGResourceLinearGradient* gradient = static_cast<RenderSVGResourceLinearGradient*>(resource);
@@ skipping 128 matching lines @@
             ts << " ";
             writeNameAndQuotedValue(ts, "filter", svgStyle->filterResource());
             ts << " ";
             writeStandardPrefix(ts, *filter, 0);
             ts << " " << filter->resourceBoundingBox(&renderer) << "\n";
         }
     }
 }
 
 } // namespace WebCore