constructor(app, page, options) {
    super();
    this.app_ = app;
    this.options_ = Object.assign({}, app.options_, options);
    this.www_ = [];
    this.page_ = page;
    this.page_.on('close', this.closed_.bind(this));
    this.page_.on('domcontentloaded', this.domContentLoaded_.bind(this));
    this.hostHandle_ = rpc.handle(new HostWindow(this));
  }
@param {!App} app
@param {!Puppeteer.Page} page Puppeteer page
@param {!Object} options