return CallQueryInterface(frag, &mRoot); }
nsHTMLFragmentContentSink::WillBuildModel(void){  if (mRoot) {    return NS_OK;  }  nsCOMPtr<nsIDOMDocumentFragment> frag;  nsresult rv = NS_NewDocumentFragment(getter_AddRefs(frag), nsnull);  NS_ENSURE_SUCCESS(rv, rv);