Make CSSParserContext be garbage collected.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
@@ skipping 46 matching lines @@
 }
 
 static const MediaQueryEvaluator& printEval() {
   DEFINE_STATIC_LOCAL(MediaQueryEvaluator, staticPrintEval,
                       (new MediaQueryEvaluator("print")));
   return staticPrintEval;
 }
 
 static StyleSheetContents* parseUASheet(const String& str) {
   StyleSheetContents* sheet =
-      StyleSheetContents::create(CSSParserContext(UASheetMode, nullptr));
+      StyleSheetContents::create(new CSSParserContext(UASheetMode));
   sheet->parseString(str);
   // User Agent stylesheets are parsed once for the lifetime of the renderer
   // process and are intentionally leaked.
   LEAK_SANITIZER_IGNORE_OBJECT(sheet);
   return sheet;
 }
 
 CSSDefaultStyleSheets::CSSDefaultStyleSheets() {
   m_defaultStyle = RuleSet::create();
   m_defaultPrintStyle = RuleSet::create();
@@ skipping 106 matching lines @@
   visitor->trace(m_televisionViewportStyleSheet);
   visitor->trace(m_xhtmlMobileProfileStyleSheet);
   visitor->trace(m_quirksStyleSheet);
   visitor->trace(m_svgStyleSheet);
   visitor->trace(m_mathmlStyleSheet);
   visitor->trace(m_mediaControlsStyleSheet);
   visitor->trace(m_fullscreenStyleSheet);
 }
 
 }  // namespace blink