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

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

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 62 matching lines @@
 static bool isAcceptableCSSStyleSheetParent(const Node& parentNode) {
   // Only these nodes can be parents of StyleSheets, and they need to call
   // clearOwnerNode() when moved out of document. Note that destructor of
   // the nodes don't call clearOwnerNode() with Oilpan.
   return parentNode.isDocumentNode() || isHTMLLinkElement(parentNode) ||
          isHTMLStyleElement(parentNode) || isSVGStyleElement(parentNode) ||
          parentNode.getNodeType() == Node::kProcessingInstructionNode;
 }
 #endif
 
+// static
+const Document* CSSStyleSheet::singleOwnerDocument(
+    const CSSStyleSheet* styleSheet) {
+  if (styleSheet)
+    return StyleSheetContents::singleOwnerDocument(styleSheet->contents());
+  return nullptr;
+}
+
 CSSStyleSheet* CSSStyleSheet::create(StyleSheetContents* sheet,
                                      CSSImportRule* ownerRule) {
   return new CSSStyleSheet(sheet, ownerRule);
 }
 
 CSSStyleSheet* CSSStyleSheet::create(StyleSheetContents* sheet,
                                      Node& ownerNode) {
   return new CSSStyleSheet(sheet, ownerNode, false,
                            TextPosition::minimumPosition());
 }
@@ skipping 348 matching lines @@
   visitor->trace(m_deviceDependentMediaQueryResults);
   visitor->trace(m_ownerNode);
   visitor->trace(m_ownerRule);
   visitor->trace(m_mediaCSSOMWrapper);
   visitor->trace(m_childRuleCSSOMWrappers);
   visitor->trace(m_ruleListCSSOMWrapper);
   StyleSheet::trace(visitor);
 }
 
 }  // namespace blink