Clean up forward declarations in Source/core/css

Source/core/svg/SVGString.h

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef SVGString_h
 #define SVGString_h
 
 #include "core/svg/properties/SVGProperty.h"
 
 namespace blink {
 
+class ExceptionState;
+
 class SVGString : public SVGPropertyBase {
 public:
     // SVGString does not have a tear-off type.
     typedef void TearOffType;
     typedef String PrimitiveType;
 
     static PassRefPtr<SVGString> create()
     {
         return adoptRef(new SVGString());
     }
@@ skipping 39 matching lines @@
 inline PassRefPtr<SVGString> toSVGString(PassRefPtr<SVGPropertyBase> passBase)
 {
     RefPtr<SVGPropertyBase> base = passBase;
     ASSERT(base->type() == SVGString::classType());
     return static_pointer_cast<SVGString>(base.release());
 }
 
 } // namespace blink
 
 #endif // SVGString_h