chromium/third_party/blink/web_tests/compositing/images/clip-on-directly-composited-image.html

<!DOCTYPE html>

<html>
<head>
  <style type="text/css" media="screen">
    img {
      width: 200px;
      height: 200px;
      clip: rect(10px 150px 150px 10px);
      position: absolute;
      z-index: 1;
    }
    
    .composited {
      will-change: transform;
      left: 200px;
    }
    
    #layers {
      position: relative;
      top: 220px;
    }
  </style>
  <script type="text/javascript" charset="utf-8">
    if (window.testRunner) {
      testRunner.dumpAsText();
      testRunner.waitUntilDone();
    }
      
    function doTest() {
      if (window.testRunner) {
        document.getElementById('layers').innerText = internals.layerTreeAsText(document);
        testRunner.notifyDone();
      }
    }
    window.addEventListener('load', doTest, false);
  </script>
</head>
<body>

  <img src="../resources/alpha-gradient-small.png">
  <img class="composited" src="../resources/alpha-gradient-small.png">

<pre id="layers">
The layer tree goes here in DRT.
</pre>
  
</body>
</html>