<!DOCTYPE html>

<html>
<head>
  <style>
    .container {
      position: relative;
      height: 300px;
      width: 300px;
      margin: 10px;
      background-color: green;
      -webkit-transition-property: opacity;
      -webkit-transition-timing-function: linear;
      -webkit-transition-duration: 5s;
    }
  
    #first {
      opacity: 0.5;
    }

    .box {
      position: absolute;
      left: 10px;
      top: 10px;
      height: 200px;
      width: 200px;
      background-color: blue;
    }

    .indicator {
      position: absolute;
      top: 150px;
      left: 150px;
      height: 100px;
      width: 100px;
      background-color: orange;
      z-index: -1;
    }
  </style>
  <script>
    if (window.testRunner)
      testRunner.waitUntilDone();

    function runTest()
    {
      var container = document.getElementById('first');
      container.style.opacity = 1;
      
      // dump the tree in the middle of the transition
      if (window.testRunner)
        window.setTimeout(function() {
          var firstElement = document.getElementById('first');
          const transition = firstElement.getAnimations()[0];
          transition.currentTime = 2500;
          transition.pause();
          testRunner.notifyDone();
        }, 0);
    }
    // FIXME: this should use runTransitionTest().
    window.addEventListener('load', runTest, false);
  </script>
</head>
<body>

  <div class="container" id="first">
    <div class="box"></div>
    <div class="indicator"></div>
  </div>

</body>
</html>