Introduce a SVGUnknownElement class for unknown SVG elements

Source/core/svg/SVGGradientElement.h

 /*
  * Copyright (C) 2004, 2005, 2006, 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 75 matching lines @@
 
     Vector<Gradient::ColorStop> buildStops();
 
 protected:
     SVGGradientElement(const QualifiedName&, Document*);
 
     bool isSupportedAttribute(const QualifiedName&);
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
     virtual void svgAttributeChanged(const QualifiedName&);
 
-    virtual bool rendererIsNeeded(const NodeRenderingContext& context) OVERRIDE { return rendererIsNeededInternal(context); }
-
 private:
     virtual bool needsPendingResourceHandling() const { return false; }
 
     virtual void childrenChanged(bool changedByParser = false, Node* beforeChange = 0, Node* afterChange = 0, int childCountDelta = 0);
 
     BEGIN_DECLARE_ANIMATED_PROPERTIES(SVGGradientElement)
         DECLARE_ANIMATED_ENUMERATION(SpreadMethod, spreadMethod, SVGSpreadMethodType)
         DECLARE_ANIMATED_ENUMERATION(GradientUnits, gradientUnits, SVGUnitTypes::SVGUnitType)
         DECLARE_ANIMATED_TRANSFORM_LIST(GradientTransform, gradientTransform)
         DECLARE_ANIMATED_STRING(Href, href)
         DECLARE_ANIMATED_BOOLEAN(ExternalResourcesRequired, externalResourcesRequired)
     END_DECLARE_ANIMATED_PROPERTIES
 };
 
 inline SVGGradientElement* toSVGGradientElement(Node* node)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!node || (node->hasTagName(SVGNames::radialGradientTag) || node->hasTagName(SVGNames::linearGradientTag)));
     return static_cast<SVGGradientElement*>(node);
 }
 
 } // namespace WebCore
 
 #endif