Clean up forward declarations in Source/core/css

Source/core/css/CSSValue.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * 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,
@@ skipping 15 matching lines @@
 #include "platform/heap/Handle.h"
 #include "platform/weborigin/KURL.h"
 #include "wtf/HashMap.h"
 #include "wtf/ListHashSet.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 class ExceptionState;
-class StyleSheetContents;
 
 enum CSSTextFormattingFlags { QuoteCSSStringIfNeeded, AlwaysQuoteCSSString };
 
 // FIXME: The current CSSValue and subclasses should be turned into internal types (StyleValue).
 // The few subtypes that are actually exposed in CSSOM can be seen in the cloneForCSSOM() function.
 // They should be handled by separate wrapper classes.
 
 // Please don't expose more CSSValue types to the web.
 class CSSValue : public RefCountedWillBeGarbageCollectedFinalized<CSSValue>, public ScriptWrappableBase {
 public:
@@ skipping 205 matching lines @@
 {
     return first ? second && first->equals(*second) : !second;
 }
 
 #define DEFINE_CSS_VALUE_TYPE_CASTS(thisType, predicate) \
     DEFINE_TYPE_CASTS(thisType, CSSValue, value, value->predicate, value.predicate)
 
 } // namespace blink
 
 #endif // CSSValue_h