nsCOMPtr<nsIPref> prefService(do_GetService(kPrefServiceCID));
nsCOMPtr<nsIPref> prefService(do_GetService(NS_PREF_CONTRACTID));
nsHTMLElementFactory::nsHTMLElementFactory(){  NS_INIT_REFCNT();  nsCOMPtr<nsIPref> prefService(do_GetService(kPrefServiceCID));  if (prefService)    prefService->GetBoolPref("nglayout.debug.enable_xbl_forms", &mUseXBLForms);}