Use new is*Element() helper functions in DOM code

Source/core/dom/RenderTreeBuilder.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Google 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
@@ skipping 62 matching lines @@
 
     return m_renderingParent->renderer();
 }
 
 bool RenderTreeBuilder::shouldCreateRenderer() const
 {
     if (!m_renderingParent)
         return false;
     if (m_node->isSVGElement()) {
         // SVG elements only render when inside <svg>, or if the element is an <svg> itself.
-        if (!m_node->hasTagName(SVGNames::svgTag) && !m_renderingParent->isSVGElement())
+        if (!isSVGSVGElement(*m_node) && !m_renderingParent->isSVGElement())
             return false;
         if (!toSVGElement(m_node)->isValid())
             return false;
     }
     RenderObject* parentRenderer = this->parentRenderer();
     if (!parentRenderer)
         return false;
     if (!parentRenderer->canHaveChildren())
         return false;
     return true;
@@ skipping 86 matching lines @@
     newRenderer->setFlowThreadState(parentRenderer->flowThreadState());
 
     RenderObject* nextRenderer = this->nextRenderer();
     textNode->setRenderer(newRenderer);
     // Parent takes care of the animations, no need to call setAnimatableStyle.
     newRenderer->setStyle(m_style.release());
     parentRenderer->addChild(newRenderer, nextRenderer);
 }
 
 }