Disable the thread-safe MQ parser for main thread

Source/core/html/parser/HTMLPreloadScanner.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/
  * Copyright (C) 2010 Google Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 77 matching lines @@
     if (match(tagImpl, linkTag))
         return linkTag.localName();
     if (match(tagImpl, scriptTag))
         return scriptTag.localName();
     ASSERT_NOT_REACHED();
     return emptyString();
 }
 
 static bool mediaAttributeMatches(const MediaValues& mediaValues, const String& attributeValue)
 {
-    RefPtrWillBeRawPtr<MediaQuerySet> mediaQueries = MediaQuerySet::create(attributeValue);
+    RefPtrWillBeRawPtr<MediaQuerySet> mediaQueries = MediaQuerySet::createOffMainThread(attributeValue);
     MediaQueryEvaluator mediaQueryEvaluator("screen", mediaValues);
     return mediaQueryEvaluator.eval(mediaQueries.get());
 }
 
 class TokenPreloadScanner::StartTagScanner {
 public:
     StartTagScanner(const StringImpl* tagImpl, PassRefPtr<MediaValues> mediaValues)
         : m_tagImpl(tagImpl)
         , m_linkIsStyleSheet(false)
         , m_matchedMediaAttribute(true)
@@ skipping 305 matching lines @@
         if (m_token.type() == HTMLToken::StartTag)
             m_tokenizer->updateStateFor(attemptStaticStringCreation(m_token.name(), Likely8Bit));
         m_scanner.scan(m_token, m_source, requests);
         m_token.clear();
     }
 
     preloader->takeAndPreload(requests);
 }
 
 }