Reduce forward declarations in core/svg

Source/core/svg/SVGAltGlyphElement.h

 /*
  * Copyright (C) 2004, 2005, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 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 13 matching lines @@
 
 #if ENABLE(SVG_FONTS)
 #include "core/SVGNames.h"
 #include "core/svg/SVGTextPositioningElement.h"
 #include "core/svg/SVGURIReference.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class ExceptionState;
-class SVGGlyphElement;
 
 class SVGAltGlyphElement FINAL : public SVGTextPositioningElement,
                                  public SVGURIReference {
 public:
     DECLARE_NODE_FACTORY(SVGAltGlyphElement);
 
     const AtomicString& glyphRef() const;
     void setGlyphRef(const AtomicString&, ExceptionState&);
     const AtomicString& format() const;
     void setFormat(const AtomicString&, ExceptionState&);
 
     bool hasValidGlyphElements(Vector<AtomicString>& glyphNames) const;
 
 private:
     explicit SVGAltGlyphElement(Document&);
 
     virtual RenderObject* createRenderer(RenderStyle*) OVERRIDE;
 };
 
 } // namespace WebCore
 
 #endif
 #endif