<html class="reftest-wait">
<head>
<script>
  async function start () {
    const canvas = document.createElement("canvas")
    const context = canvas.getContext("2d")
    context.fillStyle = "blue"
    context.fillRect(0, 0, canvas.width, canvas.height)
    const stream = canvas.captureStream()
    const track = stream.getTracks()[0]
    const recorder = new MediaRecorder(stream)
    recorder.start()
    await new Promise(r => recorder.onstart = r)
    recorder.pause()
    stream.removeTrack(track)
    recorder.resume()
    await new Promise(r => recorder.onstop = r)
    document.documentElement.removeAttribute("class")
  }

  window.addEventListener('load', start)
</script>
</head>
</html>

