docs: public void onCreate(Bundle savedInstanceState) {
          Session session = Session.getActiveSession();
          if (session == null) {
              if (savedInstanceState != null) {
                  session = Session.restoreSession(activity, null, callback, savedInstanceState);
              }
              if (session == null) {
                  session = new Session(activity);
              }
              Session.setActiveSession(session);
          }
          if (savedInstanceState != null) {
              pendingFacebookDialogCall = savedInstanceState.getParcelable(DIALOG_CALL_BUNDLE_SAVE_KEY);
          }
      }