Reduce number of header includes in SVG

Source/core/svg/SVGStyledElement.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #ifndef SVGStyledElement_h
 #define SVGStyledElement_h
 
 #include "CSSPropertyNames.h"
 #include "core/svg/SVGAnimatedString.h"
+#include "core/svg/SVGElement.h"
 #include "core/svg/SVGLocatable.h"
 #include <wtf/HashSet.h>
 #include <wtf/PassRefPtr.h>
 
 namespace WebCore {
 
 void mapAttributeToCSSProperty(HashMap<AtomicStringImpl*, CSSPropertyID>* propertyNameToIdMap, const QualifiedName& attrName);
 
 class CSSValue;
 class CSSStyleDeclaration;
@@ skipping 57 matching lines @@
 
 inline SVGStyledElement* toSVGStyledElement(Node* node)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!node || (node->isStyledElement() && node->isSVGElement()));
     return static_cast<SVGStyledElement*>(node);
 }
 
 } // namespace WebCore
 
 #endif // SVGStyledElement