Use a bitmask for SVG render object types

Source/core/rendering/svg/RenderSVGRoot.h

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2009 Google, Inc.  All rights reserved.
  * Copyright (C) 2009 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 49 matching lines @@
     virtual bool hasRelativeIntrinsicLogicalWidth() const OVERRIDE;
     virtual bool hasRelativeLogicalHeight() const OVERRIDE;
 
     // localToBorderBoxTransform maps local SVG viewport coordinates to local CSS box coordinates.
     const AffineTransform& localToBorderBoxTransform() const { return m_localToBorderBoxTransform; }
 
 private:
     virtual RenderObjectChildList* virtualChildren() { return children(); }
     virtual const RenderObjectChildList* virtualChildren() const { return children(); }
 
-    virtual bool isSVGRoot() const { return true; }
     virtual const char* renderName() const { return "RenderSVGRoot"; }
+    virtual SVGType getSVGType() const OVERRIDE { return IsSVGRoot; }
 
     virtual LayoutUnit computeReplacedLogicalWidth(ShouldComputePreferred  = ComputeActual) const OVERRIDE;
     virtual LayoutUnit computeReplacedLogicalHeight() const;
     virtual void layout();
     virtual void paintReplaced(PaintInfo&, const LayoutPoint&);
 
     virtual void willBeDestroyed();
     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle);
     virtual void addChild(RenderObject* child, RenderObject* beforeChild = 0) OVERRIDE;
     virtual void removeChild(RenderObject*) OVERRIDE;
@@ skipping 31 matching lines @@
     AffineTransform m_localToBorderBoxTransform;
     bool m_isLayoutSizeChanged : 1;
     bool m_needsBoundariesOrTransformUpdate : 1;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderSVGRoot, isSVGRoot());
 
 } // namespace WebCore
 
 #endif // RenderSVGRoot_h