Method open

third_party/subscriptions-project/swg.js:11957–11960

* Opens the notification toast. * @return {!Promise}

()

   * @return {!Promise}
   */
  open() {
    this.doc_.getBody().appendChild(this.iframe_); // Fires onload.
    return this.buildToast_();
  }

  /**
   * Builds the content of the iframe. On load, animates the toast.