Introduce isHTMLAreaElement and toHTMLAreaElement

Source/core/html/HTMLMapElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2010 Apple Inc. 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.
  *
@@ skipping 44 matching lines @@
 
 HTMLMapElement::~HTMLMapElement()
 {
 }
 
 bool HTMLMapElement::mapMouseEvent(LayoutPoint location, const LayoutSize& size, HitTestResult& result)
 {
     HTMLAreaElement* defaultArea = 0;
     Element* element = this;
     while ((element = ElementTraversal::next(element, this))) {
-        if (element->hasTagName(areaTag)) {
-            HTMLAreaElement* areaElt = static_cast<HTMLAreaElement*>(element);
+        if (isHTMLAreaElement(element)) {
+            HTMLAreaElement* areaElt = toHTMLAreaElement(element);
             if (areaElt->isDefault()) {
                 if (!defaultArea)
                     defaultArea = areaElt;
             } else if (areaElt->mapMouseEvent(location, size, result))
                 return true;
         }
     }
-    
+
     if (defaultArea) {
         result.setInnerNode(defaultArea);
         result.setURLElement(defaultArea);
     }
     return defaultArea;
 }
 
 HTMLImageElement* HTMLMapElement::imageElement()
 {
     RefPtr<HTMLCollection> images = document()->images();
@@ skipping 52 matching lines @@
 }
 
 void HTMLMapElement::removedFrom(ContainerNode* insertionPoint)
 {
     if (insertionPoint->inDocument())
         treeScope()->removeImageMap(this);
     HTMLElement::removedFrom(insertionPoint);
 }
 
 }