select(accounts, opt_config) {
    if (typeof this.config_['callbacks']['select'] === 'function') {
      this.config_['callbacks']['select'](
          undefined, firebaseui.auth.acClient.DummyApi.UNAVAILABLE_ERROR_);
    }
  }
Selects account. The callback is always invoked with a service unavailable
error.

@param {Array<Object>} accounts The local accounts to select.
@param {Object=} opt_config The optional client configuration.