setVisibility(visible) {
    this.visibility_ = visible;
    if (this.video_ && !this.visibility_) {
      this.video_.parentNode.removeChild(this.video_);
      this.video_ = null;
    }
    this.maybeAddVideoElement_();
  }
Indicates if the video should be mirrored/displayed on the page.
@param {boolean} visible whether to add the video from the source stream to
    the page