Remove isSupportedAttribute in svg

Source/core/svg/SVGTextContentElement.h

 /*
  * Copyright (C) 2004, 2005, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 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 52 matching lines @@
 
     SVGAnimatedLength* textLength() { return m_textLength.get(); }
     bool textLengthIsSpecifiedByUser() { return m_textLengthIsSpecifiedByUser; }
     SVGAnimatedEnumeration<SVGLengthAdjustType>* lengthAdjust() { return m_lengthAdjust.get(); }
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     SVGTextContentElement(const QualifiedName&, Document&);
 
-    bool isSupportedAttribute(const QualifiedName&);
     virtual bool isPresentationAttribute(const QualifiedName&) const override final;
     virtual void collectStyleForPresentationAttribute(const QualifiedName&, const AtomicString&, MutableStylePropertySet*) override final;
     virtual void svgAttributeChanged(const QualifiedName&) override;
 
     virtual bool selfHasRelativeLengths() const override;
 
 private:
     virtual bool isTextContent() const override final { return true; }
 
     RefPtrWillBeMember<SVGAnimatedLength> m_textLength;
     bool m_textLengthIsSpecifiedByUser;
     RefPtrWillBeMember<SVGAnimatedEnumeration<SVGLengthAdjustType>> m_lengthAdjust;
 };
 
 inline bool isSVGTextContentElement(const SVGElement& element)
 {
     return element.isTextContent();
 }
 
 DEFINE_SVGELEMENT_TYPE_CASTS_WITH_FUNCTION(SVGTextContentElement);
 
 } // namespace blink
 
 #endif // SVGTextContentElement_h