Disable the thread-safe MQ parser for main thread

Source/core/css/parser/BisonCSSParser-in.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 1194 matching lines @@
         declaration->addParsedProperties(m_parsedProperties);
         clearProperties();
     }
 
     if (m_observer)
         m_observer->endRuleBody(string.length(), false);
 
     return ok;
 }
 
+PassRefPtrWillBeRawPtr<MediaQuerySet> BisonCSSParser::parseMediaQueryList(const String& string)
+{
+    ASSERT(!m_mediaList);
+
+    // can't use { because tokenizer state switches from mediaquery to initial state when it sees { token.
+    // instead insert one " " (which is caught by maybe_space in CSSGrammar.y)
+    setupParser("@-internal-medialist ", string, "");
+    cssyyparse(this);
+
+    ASSERT(m_mediaList);
+    return m_mediaList.release();
+}
+
 static inline void filterProperties(bool important, const WillBeHeapVector<CSSProperty, 256>& input, WillBeHeapVector<CSSProperty, 256>& output, size_t& unusedEntries, BitArray<numCSSProperties>& seenProperties)
 {
     // Add properties in reverse order so that highest priority definitions are reached first. Duplicate definitions can then be ignored when found.
     for (int i = input.size() - 1; i >= 0; --i) {
         const CSSProperty& property = input[i];
         if (property.isImportant() != important)
             continue;
         const unsigned propertyIDIndex = property.id() - firstCSSProperty;
         if (seenProperties.get(propertyIDIndex))
             continue;
@@ skipping 947 matching lines @@
     rule->setProperties(createStylePropertySet());
     clearProperties();
 
     StyleRuleViewport* result = rule.get();
     m_parsedRules.append(rule.release());
 
     return result;
 }
 
 }