chromium/third_party/blink/web_tests/compositing/geometry/flipped-writing-mode.html

<!DOCTYPE html>

<html>
<head>
  <style>
    body {
      overflow: hidden;
    }
    .flipped {
      margin: 10px;
      height: 200px;
      width: 250px;
      background-color: silver;
      -webkit-writing-mode: vertical-rl;
    }
    
    .box {
      height: 100px;
      width: 100px;
      margin: 10px 20px;
      background-color: blue;
    }
    
    .composited {
      will-change: transform;
    }
    
    .block {
      width: 20px;
      height: 80px;
      margin: 5px;
      background-color: green;
    }
    
    #layers {
      opacity: 0; /* hide from pixel result */
    }
  </style>
  <script>
    if (window.testRunner)
      testRunner.dumpAsTextWithPixelResults();
    
    function dumpLayers()
    {
      if (window.testRunner)
        document.getElementById('layers').innerText = internals.layerTreeAsText(document);
    }
    
    window.addEventListener('load', dumpLayers, false);
  </script>
</head>
<body>

  <div class="composited flipped">
    <div class="composited box">
      <div class="block"></div>
      <div class="block"></div>
      <div class="block"></div>
      <div class="block"></div>
      <div class="block"></div>
      <div class="block"></div>
      <div class="block"></div>
      <div class="block"></div>
    </div>
  </div>

  <pre id="layers">Layer tree goes here in DRT</pre>
</body>
</html>