transitionListeners() {
    let body = this.content;
    body.style['transitionProperty'] = "font, font-size, font-size-adjust, font-stretch, font-variation-settings, font-weight, width, height";
    body.style['transitionDuration'] = "0.001ms";
    body.style['transitionTimingFunction'] = "linear";
    body.style['transitionDelay'] = "0";
    this._resizeCheck = this.resizeCheck.bind(this);
    this.document.addEventListener('transitionend', this._resizeCheck);
  }
Use css transitions to detect resize
@private