Clean up after getPropertyCSSValue

Source/core/css/CSSGridLineNamesValue.h

 /*
  * Copyright (C) 2013 Igalia, S.L. 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 27 matching lines @@
 
 class CSSGridLineNamesValue : public CSSValueList {
 public:
     static PassRefPtrWillBeRawPtr<CSSGridLineNamesValue> create()
     {
         return adoptRefWillBeNoop(new CSSGridLineNamesValue());
     }
 
     String customCSSText() const;
 
-    PassRefPtrWillBeRawPtr<CSSGridLineNamesValue> cloneForCSSOM() const;
-
     void traceAfterDispatch(Visitor* visitor) { CSSValueList::traceAfterDispatch(visitor); }
 
 private:
     CSSGridLineNamesValue();
 };
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSGridLineNamesValue, isGridLineNamesValue());
 }
 
 
 #endif