mInterimPage = (nsHistoryEntry *) nsnull;
nsSessionHistory::nsSessionHistory(){  mHistoryLength = 0;  mHistoryCurrentIndex = -1;  mIsLoadingDoc = 0;  mHistoryEntryInLoad = (nsHistoryEntry *) nsnull;   mInterimPage = (nsHistoryEntry *) nsnull;//mHistoryEntries = (nsVoidArray)0;  NS_INIT_REFCNT();}