Move isValid/isCurrentColor from Color to StyleColor

Source/core/rendering/style/StyleBackgroundData.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * 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 StyleBackgroundData_h
 #define StyleBackgroundData_h
 
-#include "core/platform/graphics/Color.h"
+#include "core/css/StyleColor.h"
 #include "core/rendering/style/FillLayer.h"
 #include "core/rendering/style/OutlineValue.h"
 #include <wtf/PassRefPtr.h>
 #include <wtf/RefCounted.h>
 
 namespace WebCore {
 
 class StyleBackgroundData : public RefCounted<StyleBackgroundData> {
 public:
     static PassRefPtr<StyleBackgroundData> create() { return adoptRef(new StyleBackgroundData); }
     PassRefPtr<StyleBackgroundData> copy() const { return adoptRef(new StyleBackgroundData(*this)); }
     ~StyleBackgroundData() { }
 
     bool operator==(const StyleBackgroundData& o) const;
     bool operator!=(const StyleBackgroundData& o) const
     {
         return !(*this == o);
     }
 
     const FillLayer& background() const { return m_background; }
-    const Color& color() const { return m_color; }
+    const StyleColor& color() const { return m_color; }
     const OutlineValue& outline() const { return m_outline; }
 
 private:
     friend class RenderStyle;
 
     StyleBackgroundData();
     StyleBackgroundData(const StyleBackgroundData&); 
 
     FillLayer m_background;
-    Color m_color;
+    StyleColor m_color;
     OutlineValue m_outline;
 };
 
 } // namespace WebCore
 
 #endif // StyleBackgroundData_h