@SuppressWarnings("deprecation") // TODO: refactor to use savedInstanceState instead
  @Override
  public Object onRetainCustomNonConfigurationInstance() {
    return users; // save state of users and currently displayed PINs
  }
Reacts to the {@link Intent} that started this activity or arrived to this activity without
restarting it (i.e., arrived via {@link #onNewIntent(Intent)}). Does nothing if the provided
intent is {@code null}.
java/com/google/android/apps/authenticator/AuthenticatorActivity.java