- fixed <rdar://problem/4550473> Reproducible hang on www.digg.com
        
        * dom/NodeList.cpp:
        (WebCore::NodeList::recursiveItem): Make NodeList caching also
        work for backwards iteration - if the requested index is before
        the last cached, but closer to it than to the start of the list,
        then search backwards from there.
        (WebCore::NodeList::itemForwardsFromCurrent): Split this out as a
        helper method.
        (WebCore::NodeList::itemBackwardsFromCurrent): New helper, similar
        to the above.
        * dom/NodeList.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@15057 268f45cc-cd09-0410-ab3c-d52691b4dbfc