Use isSVG*Element() helpers more in SVG code (Part 3)

Source/core/rendering/RenderLayerFilterInfo.cpp

 /*
  * Copyright (C) 2012 Adobe Systems Incorporated. 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 notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 109 matching lines @@
         DocumentResource* cachedSVGDocument = documentReference ? documentReference->document() : 0;
 
         if (cachedSVGDocument) {
             // Reference is external; wait for notifyFinished().
             cachedSVGDocument->addClient(this);
             m_externalSVGReferences.append(cachedSVGDocument);
         } else {
             // Reference is internal; add layer as a client so we can trigger
             // filter repaint on SVG attribute change.
             Element* filter = m_layer->renderer()->node()->document().getElementById(referenceFilterOperation->fragment());
-            if (!filter || !filter->hasTagName(SVGNames::filterTag))
+            if (!isSVGFilterElement(filter))
                 continue;
             if (filter->renderer())
                 toRenderSVGResourceContainer(filter->renderer())->addClientRenderLayer(m_layer);
             else
                 toSVGFilterElement(filter)->addClient(m_layer->renderer()->node());
             m_internalSVGReferences.append(filter);
         }
     }
 }
 
 void RenderLayerFilterInfo::removeReferenceFilterClients()
 {
     for (size_t i = 0; i < m_externalSVGReferences.size(); ++i)
         m_externalSVGReferences.at(i)->removeClient(this);
     m_externalSVGReferences.clear();
     for (size_t i = 0; i < m_internalSVGReferences.size(); ++i) {
         Element* filter = m_internalSVGReferences.at(i).get();
         if (filter->renderer())
             toRenderSVGResourceContainer(filter->renderer())->removeClientRenderLayer(m_layer);
         else
             toSVGFilterElement(filter)->removeClient(m_layer->renderer()->node());
     }
     m_internalSVGReferences.clear();
 }
 
 } // namespace WebCore