Use new Traversal<*Element> API in svg code for clarity

Source/core/svg/SVGElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
  *
  * 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
@@ skipping 735 matching lines @@
 
 void SVGElement::collectStyleForPresentationAttribute(const QualifiedName& name, const AtomicString& value, MutableStylePropertySet* style)
 {
     CSSPropertyID propertyID = cssPropertyIdForSVGAttributeName(name);
     if (propertyID > 0)
         addPropertyToPresentationAttributeStyle(style, propertyID, value);
 }
 
 bool SVGElement::haveLoadedRequiredResources()
 {
-    Node* child = firstChild();
-    while (child) {
-        if (child->isSVGElement() && !toSVGElement(child)->haveLoadedRequiredResources())
+    for (SVGElement* child = Traversal<SVGElement>::firstChild(*this); child; child = Traversal<SVGElement>::nextSibling(*child)) {
+        if (!child->haveLoadedRequiredResources())
             return false;
-        child = child->nextSibling();
     }
     return true;
 }
 
 static inline void collectInstancesForSVGElement(SVGElement* element, HashSet<SVGElementInstance*>& instances)
 {
     ASSERT(element);
     if (element->containingShadowRoot())
         return;
 
@@ skipping 362 matching lines @@
         animatableAttributes.add(SVGNames::zAttr);
     }
 
     if (name == classAttr)
         return true;
 
     return animatableAttributes.contains(name);
 }
 #endif
 }