Disable the thread-safe MQ parser for main thread

Source/core/css/MediaList.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2008, 2009, 2010, 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 28 matching lines @@
 class MediaQuery;
 
 class MediaQuerySet : public RefCountedWillBeGarbageCollected<MediaQuerySet> {
     DECLARE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(MediaQuerySet);
 public:
     static PassRefPtrWillBeRawPtr<MediaQuerySet> create()
     {
         return adoptRefWillBeNoop(new MediaQuerySet());
     }
     static PassRefPtrWillBeRawPtr<MediaQuerySet> create(const String& mediaString);
+    static PassRefPtrWillBeRawPtr<MediaQuerySet> createOffMainThread(const String& mediaString);
 
     bool set(const String&);
     bool add(const String&);
     bool remove(const String&);
 
     void addMediaQuery(PassOwnPtrWillBeRawPtr<MediaQuery>);
 
     const WillBeHeapVector<OwnPtrWillBeMember<MediaQuery> >& queryVector() const { return m_queries; }
 
     String mediaText() const;
@@ skipping 56 matching lines @@
     // Cleared in the ~CSSMediaRule and ~CSSImportRule destructors when oilpan is not enabled.
     RawPtrWillBeMember<CSSRule> m_parentRule;
 };
 
 // Adds message to inspector console whenever dpi or dpcm values are used for "screen" media.
 void reportMediaQueryWarningIfNeeded(Document*, const MediaQuerySet*);
 
 } // namespace
 
 #endif