containing-block-removed.html | Explore in Territory

<!DOCTYPE html>
<html>
<head>
  <style>
    #container {
      will-change: transform;
      position: absolute;
      left: 200px;
      top: 100px;
      width: 100px;
      height: 100px;
      background-color: blue;
    }

    .fixed {
      position: fixed;
      left: 50px;
      top: 50px;
      width: 75px;
      height: 75px;
      background-color: green
    }
  </style>
  <script src="../resources/text-based-repaint.js"></script>
  <script>
    function repaintTest()
    {
      // Removing "will-change: transform" to the container div should make this
      // div no longer be the containing block for its fixed position descendant.
      document.getElementById("container").style.willChange = "top";
    }
    onload = runRepaintAndPixelTest;
  </script>
</head>

<body>
  <div id="container">
    <div class="fixed"></div>
  </div>
</body>

</html>

chromium/third_party/blink/web_tests/paint/invalidation/compositing/containing-block-removed.html