code: function logAdditionalUserInfo(response) {
    if (response.additionalUserInfo) {
      if (response.additionalUserInfo.username) {
        log(response.additionalUserInfo['providerId'] + ' username: ' +
            response.additionalUserInfo.username);
      }
      if (response.additionalUserInfo.profile) {
        log(response.additionalUserInfo['providerId'] + ' profile information:');
        log(JSON.stringify(response.additionalUserInfo.profile, null, 2));
      }
      if (typeof response.additionalUserInfo.isNewUser !== 'undefined') {
        log(response.additionalUserInfo['providerId'] + ' isNewUser: ' +
            response.additionalUserInfo.isNewUser);
      }
    }
  }
docs: Logs additional user info returned by a sign-in event, if available.
  @param {!Object} response