Remove isSupportedAttribute in svg

Source/core/svg/SVGRadialGradientElement.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 31 matching lines @@
     SVGAnimatedLength* r() const { return m_r.get(); }
     SVGAnimatedLength* fx() const { return m_fx.get(); }
     SVGAnimatedLength* fy() const { return m_fy.get(); }
     SVGAnimatedLength* fr() const { return m_fr.get(); }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit SVGRadialGradientElement(Document&);
 
-    bool isSupportedAttribute(const QualifiedName&);
     virtual void svgAttributeChanged(const QualifiedName&) override;
 
     virtual LayoutObject* createLayoutObject(const ComputedStyle&) override;
 
     virtual bool selfHasRelativeLengths() const override;
 
     RefPtrWillBeMember<SVGAnimatedLength> m_cx;
     RefPtrWillBeMember<SVGAnimatedLength> m_cy;
     RefPtrWillBeMember<SVGAnimatedLength> m_r;
     RefPtrWillBeMember<SVGAnimatedLength> m_fx;
     RefPtrWillBeMember<SVGAnimatedLength> m_fy;
     RefPtrWillBeMember<SVGAnimatedLength> m_fr;
 };
 
 } // namespace blink
 
 #endif // SVGRadialGradientElement_h