return NS_OK;
nsWebShell::DestroyChildren(){  PRInt32 i, n = mChildren.Count();  for (i = 0; i < n; i++) {    nsIDocShellTreeItem * shell = (nsIDocShellTreeItem*) mChildren.ElementAt(i);    shell->SetParent(nsnull);    nsCOMPtr<nsIBaseWindow> shellWin(do_QueryInterface(shell));    shellWin->Destroy();    NS_RELEASE(shell);  }  mChildren.Clear();}