constructor(imaAd, video) {
    /** @private {google.ima.dai.api.Ad} */
    this.ad_ = imaAd;

    /** @private {?google.ima.dai.api.AdProgressData} */
    this.adProgressData_ = null;

    /** @private {HTMLMediaElement} */
    this.video_ = video;
  }
@param {google.ima.dai.api.Ad} imaAd
@param {HTMLMediaElement} video