StyleResolver should update RuleSets lazily.

Source/core/css/MediaQueryMatcher.cpp

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  *  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,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 66 matching lines @@
 PassOwnPtr<MediaQueryEvaluator> MediaQueryMatcher::prepareEvaluator() const
 {
     if (!m_document || !m_document->frame())
         return nullptr;
 
     Element* documentElement = m_document->documentElement();
     if (!documentElement)
         return nullptr;
 
     StyleResolver* styleResolver = m_document->styleResolver();
-    if (!styleResolver)
-        return nullptr;
+    ASSERT(styleResolver);
+    appendPendingStyleSheetsIfNeeded(styleResolver);
 
     RefPtr<RenderStyle> rootStyle = styleResolver->styleForElement(documentElement, 0 /*defaultParent*/, DisallowStyleSharing, MatchOnlyUserAgentRules);
 
     return adoptPtr(new MediaQueryEvaluator(mediaType(), m_document->frame(), rootStyle.get()));
 }
 
 bool MediaQueryMatcher::evaluate(const MediaQuerySet* media)
 {
     if (!media)
         return false;
@@ skipping 51 matching lines @@
     ++m_evaluationRound;
     OwnPtr<MediaQueryEvaluator> evaluator = prepareEvaluator();
     if (!evaluator)
         return;
 
     for (size_t i = 0; i < m_listeners.size(); ++i)
         m_listeners[i]->evaluate(scriptState, evaluator.get());
 }
 
 }