rv = prefs->SetCharPref(BROWSER_HISTORY_LAST_PAGE_VISITED_PREF, aURL);
rv = prefs->SetCharPref(BROWSER_HISTORY_LAST_PAGE_VISITED_PREF, (const char *)mLastPageVisited);
nsGlobalHistory::SaveLastPageVisited(const char *aURL){  nsresult rv;  if (!aURL) return NS_ERROR_FAILURE;    NS_WITH_SERVICE(nsIPref, prefs, kPrefCID, &rv);  if (NS_FAILED(rv)) return rv;  rv = prefs->SetCharPref(BROWSER_HISTORY_LAST_PAGE_VISITED_PREF, aURL);#ifdef DEBUG_LAST_PAGE_VISITED  printf("XXX saving last page visited as: %s\n", aURL);#endif /* DEBUG_LAST_PAGE_VISITED */  return rv;}