<!DOCTYPE html>
<!--
 | Test case to handle a particular bug where a DCHECK could result when a
 | pseudoelement's animations/transitions are not cleared properly while
 | moving from a parent's "display: none" to the main div's "display: none".
 | In the end, we expect the final result to be that no DCHECKs get set off,
 | and that the transition appears to have been fully completed.
 -->
<html>
<head>
  <style>
    #block {
      width: 100px;
      height: 100px;
      background-color: yellow;
      font-size: 30px;
    }
    #block::after {
      content: "";
      display:block;
      transform: translateX(100px);
      width: 100px;
      height: 100px;
      background-color: #0f0;
      transition: background-color 1s linear;
    }
  </style>
</head>
<body>
  <div id="parent">
    <div id="block"></div>
  </div>

  <script>
    if (window.testRunner) {
      window.testRunner.waitUntilDone();
    }

    var parentDiv = document.getElementById('parent');
    var blockDiv = document.getElementById('block');

    window.addEventListener('load', function() {
      if (window.testRunner) {
        // Do a layout upon the load event so that we setup our source styles
        // that we will be transitioning from.
        window.testRunner.DoNonMeasuredLayout();
      }

      // Modify the rule that targets the pseudo-element, to trigger the
      // transition.
      var sheet = document.styleSheets[0];
      var rules = sheet.cssRules;
      rules[1].style.backgroundColor = '#00f';

      if (window.testRunner) {
        // Do a layout to start the transition.
        window.testRunner.DoNonMeasuredLayout();
      }

      // Set the parent div's display to none.  This should have the effect
      // of hiding the parent div and cancelling all descendant animations
      // and transitions, like the one we started above.
      parentDiv.style.display = "none";

      if (window.testRunner) {
        window.testRunner.DoNonMeasuredLayout();
      }

      // Reveal the parent div but hide the main div at the same time.  This
      // should result in the main div having its computed style calculated
      // again, even though we do nothing with it because it still has its
      // display set to none.  This is mostly just a sanity check to make
      // sure no DCHECKs go off, as a bug had been found in this case before.
      parentDiv.style.display = "block";
      blockDiv.style.display = "none";

      if (window.testRunner) {
        // Run the transition a bit so that it is started but not completed.
        window.testRunner.AdvanceClockByMs(500);
        window.testRunner.DoNonMeasuredLayout();

        blockDiv.style.display = "block";

        // Measure that the transition should now appear to be fully completed.
        window.testRunner.notifyDone();
      }
    });
  </script>

</body>
</html>