Use new is*Element() helper functions more in web/ code

Source/web/WebPageSerializer.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 91 matching lines @@
 
     return element->document().completeURL(value);
 }
 
 void retrieveResourcesForElement(Element* element,
                                  Vector<LocalFrame*>* visitedFrames,
                                  Vector<LocalFrame*>* framesToVisit,
                                  Vector<KURL>* frameURLs,
                                  Vector<KURL>* resourceURLs)
 {
+    ASSERT(element);
     // If the node is a frame, we'll process it later in retrieveResourcesForFrame.
-    if ((element->hasTagName(HTMLNames::iframeTag) || element->hasTagName(HTMLNames::frameTag)
-        || element->hasTagName(HTMLNames::objectTag) || element->hasTagName(HTMLNames::embedTag))
+    if ((isHTMLIFrameElement(*element) || isHTMLFrameElement(*element)
+        || isHTMLObjectElement(*element) || isHTMLEmbedElement(*element))
             && element->isFrameOwnerElement()) {
         if (LocalFrame* frame = toHTMLFrameOwnerElement(element)->contentFrame()) {
             if (!visitedFrames->contains(frame))
                 framesToVisit->append(frame);
             return;
         }
     }
 
     KURL url = getSubResourceURLFromElement(element);
     if (url.isEmpty() || !url.isValid())
@@ skipping 164 matching lines @@
 
 WebString WebPageSerializer::generateBaseTagDeclaration(const WebString& baseTarget)
 {
     if (baseTarget.isEmpty())
         return String("<base href=\".\">");
     String baseString = "<base href=\".\" target=\"" + static_cast<const String&>(baseTarget) + "\">";
     return baseString;
 }
 
 } // namespace blink