chromium/content/test/data/pointerlock_on_dropped_elem.html

<div id="target">
  <div></div>
</div>
<script>
  function lock() {
      document.getElementById("target").firstElementChild.requestPointerLock();
  }

  function replace() {
      let target = document.getElementById("target");
      target.removeChild(target.firstElementChild);
      target.appendChild(document.createElement("div"));
  }

  document.addEventListener("click", () => {
      setTimeout(lock, 0);
      setTimeout(replace, 0);
      setTimeout(lock, 0);
  });
</script>