Split the CSSParserContext class out of CSSParserMode into its own file.

third_party/WebKit/Source/core/layout/LayoutThemeFontProvider.h

 /*
  * Copyright (C) 2012 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 12 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef LayoutThemeFontProvider_h
 #define LayoutThemeFontProvider_h
 
 #include "core/CSSValueKeywords.h"
 #include "core/CoreExport.h"
 #include "platform/fonts/FontTraits.h"
 #include "wtf/Allocator.h"
+#include "wtf/text/AtomicString.h"
 
 namespace blink {
 
 class CORE_EXPORT LayoutThemeFontProvider {
   STATIC_ONLY(LayoutThemeFontProvider);
 
  public:
   static void systemFont(CSSValueID systemFontID,
                          FontStyle&,
                          FontWeight&,
                          float& fontSize,
                          AtomicString& fontFamily);
   static void setDefaultFontSize(int);
 
  protected:
   static const WTF::AtomicString& defaultGUIFont();
 
   static float s_defaultFontSize;
 };
 
 }  // namespace blink
 
 #endif  // LayoutThemeFontProvider_h