Method whenViewportLayoutComplete_

src/service/performance-impl.js:775–787

* Returns a promise that is resolved when resources in viewport * have been finished being laid out. * @return {!Promise} * @private

()

   * @private
   */
  whenViewportLayoutComplete_() {
    return this.resources_.whenFirstPass().then(() => {
      const {documentElement} = this.win.document;
      const size = Services.viewportForDoc(documentElement).getSize();
      const rect = layoutRectLtwh(0, 0, size.width, size.height);
      return whenContentIniLoad(
        documentElement,
        this.win,
        rect,
        /* isInPrerender */ true
      );
    });
  }

  /**
   * Ticks a timing event.