Introduce toSVGTextElement(), and use it

Source/core/rendering/svg/RenderSVGText.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) 2006 Alexander Kellett <lypanov@kde.org>
  * Copyright (C) 2006 Oliver Hunt <ojh16@student.canterbury.ac.nz>
  * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) Research In Motion Limited 2010-2012. All rights reserved.
  * Copyright (C) 2012 Google Inc.
  *
@@ skipping 332 matching lines @@
     }
 }
 
 void RenderSVGText::layout()
 {
     ASSERT(needsLayout());
     LayoutRepainter repainter(*this, SVGRenderSupport::checkForSVGRepaintDuringLayout(this));
 
     bool updateCachedBoundariesInParents = false;
     if (m_needsTransformUpdate) {
-        SVGTextElement* text = static_cast<SVGTextElement*>(node());
-        m_localTransform = text->animatedLocalTransform();
+        m_localTransform = toSVGTextElement(node())->animatedLocalTransform();
         m_needsTransformUpdate = false;
         updateCachedBoundariesInParents = true;
     }
 
     if (!everHadLayout()) {
         // When laying out initially, collect all layout attributes, build the character data map,
         // and propogate resulting SVGLayoutAttributes to all RenderSVGInlineText children in the subtree.
         ASSERT(m_layoutAttributes.isEmpty());
         collectLayoutAttributes(this, m_layoutAttributes);
         updateFontInAllDescendants(this);
@@ skipping 187 matching lines @@
     return 0;
 }
 
 // Fix for <rdar://problem/8048875>. We should not render :first-letter CSS Style
 // in a SVG text element context.
 void RenderSVGText::updateFirstLetter()
 {
 }
 
 }