Forward declare StyleVariableData in StyleRareInheritedData instead of including it

third_party/WebKit/Source/core/style/StyleRareInheritedData.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
@@ skipping 10 matching lines @@
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef StyleRareInheritedData_h
 #define StyleRareInheritedData_h
 
 #include "core/CoreExport.h"
 #include "core/css/StyleColor.h"
 #include "core/style/DataRef.h"
-#include "core/style/StyleVariableData.h"
 #include "platform/Length.h"
 #include "platform/graphics/Color.h"
 #include "platform/heap/Handle.h"
 #include "platform/text/TabSize.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefVector.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
 
 class AppliedTextDecoration;
 class CursorData;
 class QuotesData;
 class ShadowList;
 class StyleImage;
+class StyleVariableData;
 
 typedef RefVector<AppliedTextDecoration> AppliedTextDecorationList;
 #if ENABLE(OILPAN)
 typedef HeapVector<CursorData> CursorList;
 #else
 typedef RefVector<CursorData> CursorList;
 #endif
 
 // This struct is for rarely used inherited CSS3, CSS2, and WebKit-specific properties.
 // By grouping them together, we save space, and only allocate this object when someone
@@ skipping 103 matching lines @@
     RefPtr<StyleVariableData> variables;
 
 private:
     StyleRareInheritedData();
     StyleRareInheritedData(const StyleRareInheritedData&);
 };
 
 } // namespace blink
 
 #endif // StyleRareInheritedData_h