0 -> nullptr for UseCounter pointer in CSSParserContext.

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 83 matching lines @@
 }
 
 CSSStyleSheet* CSSStyleSheet::createInline(StyleSheetContents* sheet, Node* ownerNode, const TextPosition& startPosition)
 {
     ASSERT(sheet);
     return new CSSStyleSheet(sheet, ownerNode, true, startPosition);
 }
 
 CSSStyleSheet* CSSStyleSheet::createInline(Node* ownerNode, const KURL& baseURL, const TextPosition& startPosition, const String& encoding)
 {
-    CSSParserContext parserContext(ownerNode->document(), 0, baseURL, encoding);
+    CSSParserContext parserContext(ownerNode->document(), nullptr, baseURL, encoding);
     StyleSheetContents* sheet = StyleSheetContents::create(baseURL.getString(), parserContext);
     return new CSSStyleSheet(sheet, ownerNode, true, startPosition);
 }
 
 CSSStyleSheet::CSSStyleSheet(StyleSheetContents* contents, CSSImportRule* ownerRule)
     : m_contents(contents)
     , m_isInlineStylesheet(false)
     , m_isDisabled(false)
     , m_ownerNode(nullptr)
     , m_ownerRule(ownerRule)
@@ skipping 325 matching lines @@
     visitor->trace(m_mediaQueries);
     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