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

Source/core/events/EventPath.cpp

 /*
  * Copyright (C) 2013 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.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 48 matching lines @@
         return referenceNode->parentNode();
 
     if (!referenceNode->isSVGElement() || !referenceNode->isInShadowTree())
         return referenceNode;
 
     // Spec: The event handling for the non-exposed tree works as if the referenced element had been textually included
     // as a deeply cloned child of the 'use' element, except that events are dispatched to the SVGElementInstance objects.
     Node& rootNode = referenceNode->treeScope().rootNode();
     Element* shadowHostElement = rootNode.isShadowRoot() ? toShadowRoot(rootNode).host() : 0;
     // At this time, SVG nodes are not supported in non-<use> shadow trees.
-    if (!shadowHostElement || !shadowHostElement->hasTagName(SVGNames::useTag))
+    if (!isSVGUseElement(shadowHostElement))
         return referenceNode;
-    SVGUseElement* useElement = toSVGUseElement(shadowHostElement);
-    if (SVGElementInstance* instance = useElement->instanceForShadowTreeElement(referenceNode))
+    SVGUseElement& useElement = toSVGUseElement(*shadowHostElement);
+    if (SVGElementInstance* instance = useElement.instanceForShadowTreeElement(referenceNode))
         return instance;
 
     return referenceNode;
 }
 
 static inline bool inTheSameScope(ShadowRoot* shadowRoot, EventTarget* target)
 {
     return target->toNode() && target->toNode()->treeScope().rootNode() == shadowRoot;
 }
 
@@ skipping 292 matching lines @@
 
 #ifndef NDEBUG
 void EventPath::checkReachability(TreeScope& treeScope, TouchList& touchList)
 {
     for (size_t i = 0; i < touchList.length(); ++i)
         ASSERT(touchList.item(i)->target()->toNode()->treeScope().isInclusiveOlderSiblingShadowRootOrAncestorTreeScopeOf(treeScope));
 }
 #endif
 
 } // namespace