Make CSSParserContext be garbage collected.

third_party/WebKit/Source/core/dom/StyleEngine.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 129 matching lines @@
   m_injectedAuthorStyleSheets.push_back(TraceWrapperMember<CSSStyleSheet>(
       this, CSSStyleSheet::create(authorSheet, *m_document)));
   markDocumentDirty();
 }
 
 CSSStyleSheet& StyleEngine::ensureInspectorStyleSheet() {
   if (m_inspectorStyleSheet)
     return *m_inspectorStyleSheet;
 
   StyleSheetContents* contents =
-      StyleSheetContents::create(CSSParserContext(*m_document, nullptr));
+      StyleSheetContents::create(CSSParserContext::create(*m_document));
   m_inspectorStyleSheet = CSSStyleSheet::create(contents, *m_document);
   markDocumentDirty();
   // TODO(rune@opera.com): Making the active stylesheets up-to-date here is
   // required by some inspector tests, at least. I theory this should not be
   // necessary. Need to investigate to figure out if/why.
   updateActiveStyle();
   return *m_inspectorStyleSheet;
 }
 
 void StyleEngine::addPendingSheet(StyleEngineContext& context) {
@@ skipping 976 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(StyleEngine) {
   for (auto sheet : m_injectedAuthorStyleSheets) {
     visitor->traceWrappers(sheet);
   }
   visitor->traceWrappers(m_documentStyleSheetCollection);
 }
 
 }  // namespace blink