chromium/third_party/blink/web_tests/compositing/visibility/layer-visible-content.html

<html>
<head>
  <style type="text/css">
    body {
        margin: 0;
        overflow: hidden;
    }
    
    .container {
        visibility: hidden;
        position: absolute;
        width: 200px;
        height: 200px;
        overflow: hidden;
        z-index: 0;
    }
    
    .box {
        height: 100px;
        width: 100px;
    }
    
    .indicator {
        position: absolute;
        top: 0;
        left: 0;
        background-color:red;
    }
    
    .visible-box {
        background-color:green;
    }
    .composited {
        will-change: transform;
        height: 10px;
        width: 10px;
    }
    pre {
        opacity: 0; /* hide in pixel result */
        height: 16px; /* avoid platform-dependent height difference of hidden text layer-tree */
    }
  </style>
  <script>
    if (window.testRunner)
        testRunner.dumpAsTextWithPixelResults();
    
    function dumpLayers()
    {
        if (window.testRunner)
            document.getElementById('layer-tree').innerText = internals.layerTreeAsText(document);
    }
    window.addEventListener('load', dumpLayers, false);
  </script>
</head>

<body>
  <!-- You should see a green box in the top left, and no red. -->
  <div class="indicator box"></div>

  <div class="container">
    <div style="position: relative;">
      <div style="visibility:visible;">
        <div class="visible-box box">
          <div class="composited box"></div>
        </div>
      </div>
    </div>
  </div>
<pre id="layer-tree">Layer tree goes here in DRT</pre>
</body>
</html>