Change CSSParserContext to have a Document handle (vs UseCounter).

third_party/WebKit/Source/core/css/CSSStyleSheet.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010, 2012 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.
  *
@@ skipping 29 matching lines @@
 class ExceptionState;
 class MediaQuerySet;
 class SecurityOrigin;
 class StyleSheetContents;
 
 class CORE_EXPORT CSSStyleSheet final : public StyleSheet {
   DEFINE_WRAPPERTYPEINFO();
   WTF_MAKE_NONCOPYABLE(CSSStyleSheet);
 
  public:
+  static const Document* singleOwnerDocument(const CSSStyleSheet*);
+
   static CSSStyleSheet* create(StyleSheetContents*,
                                CSSImportRule* ownerRule = nullptr);
   static CSSStyleSheet* create(StyleSheetContents*, Node& ownerNode);
   static CSSStyleSheet* createInline(
       Node&,
       const KURL&,
       const TextPosition& startPosition = TextPosition::minimumPosition(),
       const String& encoding = String());
   static CSSStyleSheet* createInline(
       StyleSheetContents*,
@@ skipping 136 matching lines @@
 
 DEFINE_TYPE_CASTS(CSSStyleSheet,
                   StyleSheet,
                   sheet,
                   sheet->isCSSStyleSheet(),
                   sheet.isCSSStyleSheet());
 
 }  // namespace blink
 
 #endif