Forward declare StyleVariableData in StyleRareInheritedData instead of including it

third_party/WebKit/Source/core/style/ComputedStyle.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, 2009, 2010, 2011 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 89 matching lines @@
 
 namespace blink {
 
 using std::max;
 
 class FilterOperations;
 
 class AppliedTextDecoration;
 class BorderData;
 struct BorderEdge;
+class CSSVariableData;
 class CounterContent;
 class Font;
 class FontMetrics;
 class RotateTransformOperation;
 class ScaleTransformOperation;
 class ShadowList;
 class StyleImage;
 class StyleInheritedData;
 class StylePath;
 class StyleResolver;
@@ skipping 1888 matching lines @@
 }
 
 inline bool ComputedStyle::hasPseudoElementStyle() const
 {
     return noninherited_flags.pseudoBits & PSEUDO_ELEMENT_MASK;
 }
 
 } // namespace blink
 
 #endif // ComputedStyle_h