Reviewed by Brady.

        fix <rdar://problem/5908580> 10A58: Dictionary Panel hangs in WebCore::Cache::pruneDeadResources()

        * loader/Cache.cpp:
        (WebCore::Cache::requestUserCSSStyleSheet):
        Add a call to resourceAccessed() to more closely mirror what is done in requestResource()
        (WebCore::Cache::insertInLRUList):
        Assert that any resource in the LRU list has been accessed.  This is early detection of a
        potential hang later when pruning resources, and also agrees with the early return in 
        removeFromLRUList().



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@33940 268f45cc-cd09-0410-ab3c-d52691b4dbfc