inject() {
    window.onYouTubeIframeAPIReady = this.onYTReady.bind(this);
    const tag = document.createElement('script');
    tag.src = `https://www.youtube.com/iframe_api`;
    const firstScriptTag = document.getElementsByTagName('script')[0];
    firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);
  }
Injects the YouTube iFrame API into the page.