chromium/third_party/blink/web_tests/external/wpt/css/css-backgrounds/background-size-percentage-root-ref.html

<!doctype html>
<title>Percentage background-size on the root</title>
<style>
  div {
    width: 100px;
    height: 50px;
    background-color: lime;
    position: absolute;
    top: 0;
    left: 0;
  }
</style>
<div></div>