Have srcset respond to viewport changes

Source/core/css/MediaQueryList.h

 /*
  * 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 35 matching lines @@
     bool matches();
 
     void addListener(PassRefPtrWillBeRawPtr<MediaQueryListListener>);
     void removeListener(PassRefPtrWillBeRawPtr<MediaQueryListListener>);
 
     void mediaFeaturesChanged(WillBeHeapVector<RefPtrWillBeMember<MediaQueryListListener> >* listenersToNotify);
 
     void trace(Visitor*);
 
     void documentDetached();
+    void alwaysUpdate() { m_alwaysUpdate = true; }
 
 private:
     MediaQueryList(PassRefPtrWillBeRawPtr<MediaQueryMatcher>, PassRefPtrWillBeRawPtr<MediaQuerySet>);
 
     bool updateMatches();
 
     RefPtrWillBeMember<MediaQueryMatcher> m_matcher;
     RefPtrWillBeMember<MediaQuerySet> m_media;
     typedef WillBeHeapListHashSet<RefPtrWillBeMember<MediaQueryListListener> > ListenerList;
     ListenerList m_listeners;
     bool m_matchesDirty;
     bool m_matches;
+    bool m_alwaysUpdate;
 };
 
 }
 
 #endif // MediaQueryList_h