Use a bitmask for SVG render object types

Source/core/rendering/svg/RenderSVGViewportContainer.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.
  * 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 25 matching lines @@
 
     bool isLayoutSizeChanged() const { return m_isLayoutSizeChanged; }
     virtual bool didTransformToRootUpdate() { return m_didTransformToRootUpdate; }
 
     virtual void determineIfLayoutSizeChanged();
     virtual void setNeedsTransformUpdate() { m_needsTransformUpdate = true; }
 
     virtual void paint(PaintInfo&, const LayoutPoint&) OVERRIDE;
 
 private:
-    virtual bool isSVGViewportContainer() const { return true; }
+    virtual SVGType getSVGType() const OVERRIDE { return IsSVGViewportContainer; }
     virtual const char* renderName() const { return "RenderSVGViewportContainer"; }
 
     AffineTransform viewportTransform() const;
     virtual const AffineTransform& localToParentTransform() const { return m_localToParentTransform; }
 
     virtual void calcViewport();
     virtual bool calculateLocalTransform();
 
     virtual void applyViewportClip(PaintInfo&);
     virtual bool pointIsInsideViewportClip(const FloatPoint& pointInParent);
 
     FloatRect m_viewport;
     mutable AffineTransform m_localToParentTransform;
     bool m_didTransformToRootUpdate : 1;
     bool m_isLayoutSizeChanged : 1;
     bool m_needsTransformUpdate : 1;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderSVGViewportContainer, isSVGViewportContainer());
 
 } // namespace WebCore
 
 #endif // RenderSVGViewportContainer_h