<!DOCTYPE html>
<html class="reftest-wait reftest-no-flush">
<title>Bug 1298742</title>
<style>
div {
  width: 100px;
  height: 100px;
  background: blue;
  transform: translate(10px);
}
</style>
<div id="target"></div>
<script>
  const MS_PER_SEC = 1000;
  var elem = document.getElementById("target");
  var animA =
    elem.animate({ transform: [ 'translate(0px)', 'translate(60px)' ] },
                 100 * MS_PER_SEC);
  var animB =
    elem.animate({ transform: [ 'translate(60px)', 'translate(0px)' ] },
                 100 * MS_PER_SEC);
  animA.pause();
  animB.pause();

  Promise.all([animA.ready, animB.ready]).then(function() {
    animB.effect = null;
    requestAnimationFrame(function() {
      document.documentElement.classList.remove("reftest-wait");
    });
  });
</script>
</html>