chromium/third_party/blink/web_tests/compositing/squashing/transform-squashed-owner.html

<!DOCTYPE html>
<html>
<head>
  <style>
    .set {
      position: absolute;
      top: 8px;
    }
    .box {
      height: 100px;
      width: 100px;
      background-color: lightblue;
    }
    .squashed {
      height: 40px;
      width: 40px;
      background-color: lightgreen;
      position: absolute;
      left: 16px;
    }
    .rotated {
      transform: rotate(10deg);
    }
  </style>
</head>
<body>
    <!-- This test checks that transforming the owner of a squashed layer only transforms that layer, and not the squashed layers. -->

    <!-- This div will be the "owner" of the squashing layer -->
    <div id="target" class="box"></div>
    <!-- These divs will be squashed into a layer containing them and the owner -->
    <div class="squashed" style="top: 4px"></div>
    <div class="squashed" style="top: 54px"></div>
</body>
  <script>
      document.getElementById("target").classList.add("rotated");

  </script>
</html>