隐藏方法:

video::-webkit-media-controls{
  overflow:hidden !important;
}
video::-webkit-media-controls-enclosure{
  width: calc(100% + 80px);
  margin-left: auto;
}

参考:

https://github.com/WICG/controls-list/blob/gh-pages/explainer.md
https://developers.google.com/web/updates/2017/03/chrome-58-media-updates#controlslist
http://www.lichen100.com/article/49.html