Add support for SVG Clip paths in HTML

Source/core/svg/SVGClipPathElement.h

 /*
  * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 16 matching lines @@
 #include "core/svg/SVGGraphicsElement.h"
 #include "core/svg/SVGUnitTypes.h"
 
 namespace blink {
 
 class RenderObject;
 
 class SVGClipPathElement FINAL : public SVGGraphicsElement {
 public:
     DECLARE_NODE_FACTORY(SVGClipPathElement);
+    virtual void trace(Visitor*) OVERRIDE;
+
     SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>* clipPathUnits() { return m_clipPathUnits.get(); }
 
     virtual bool supportsFocus() const OVERRIDE { return false; }
 
+    void addClient(Node*);
+    void removeClient(Node*);
+
 private:
     explicit SVGClipPathElement(Document&);
 
     virtual bool needsPendingResourceHandling() const OVERRIDE { return false; }
 
     bool isSupportedAttribute(const QualifiedName&);
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
     virtual void svgAttributeChanged(const QualifiedName&) OVERRIDE;
     virtual void childrenChanged(const ChildrenChange&) OVERRIDE;
 
     virtual RenderObject* createRenderer(RenderStyle*) OVERRIDE;
 
     RefPtr<SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType> > m_clipPathUnits;
+
+    HashSet<RefPtr<Node> > m_clientsToAdd;
 };
 
 }
 
 #endif