chromium/third_party/blink/web_tests/compositing/overflow/overflow-with-negative-z-index-child.html

<!doctype html>
<style>
  ::-webkit-scrollbar {
    display: none;
  }
  #scroller {
    position: absolute;
    width: 400px;
    height: 400px;
    overflow-y: scroll;
    will-change: transform;
  }
  #container {
    transform: translate(0, 0);
  }
  #rect {
    width: 100px;
    height: 100px;
    background: green;
    position: absolute;
    z-index: -5;
  }
</style>
This test passes if there is a green box.
<div id="scroller">
  <div id="container">
    <div id="rect"></div>
  </div>
  <div id="forcescroll" style="height: 1000px;"></div>
</div>