Method constructor

src/service/ampdoc-impl.js:795–805

* @param {!Window} win * @param {!AmpDocOptions=} opt_options

(win, opt_options)

   * @param {!AmpDocOptions=} opt_options
   */
  constructor(win, opt_options) {
    super(win, /* parent */ null, opt_options);

    /** @private @const {!Promise<!Element>} */
    this.bodyPromise_ = this.win.document.body
      ? Promise.resolve(this.win.document.body)
      : waitForBodyOpenPromise(this.win.document).then(() => this.getBody());

    /** @private @const {!Promise} */
    this.readyPromise_ = whenDocumentReady(this.win.document);
  }

  /** @override */
  isSingleDoc() {