chromium/third_party/blink/perf_tests/accessibility/many-nodes-toggle-aria-hidden.html

<!DOCTYPE html>
<html>
<head>
  <style>
    #root1, #root2 {
        width: 100%;
        padding: 5px;
    }
    .child {
        border: 1px solid black;
        height: 10px;
        width: 10px;
        margin: -1px;
        display: inline-block;
    }
  </style>
  <script src="../resources/runner.js"></script>
</head>
<body>
<div id="container"></div>
</body>

<script>
var isDone = false;
var startTime;

// Ensure test content is generated before page load, so that the test
// construction is not part of the collected traces.
var container = document.getElementById('container');
generateAllContent();

function runTest() {
  if (startTime) {
    PerfTestRunner.measureValueAsync(PerfTestRunner.now() - startTime);
    PerfTestRunner.addRunTestEndMarker();
  }
  if (!isDone) {
    PerfTestRunner.addRunTestStartMarker();
    startTime = PerfTestRunner.now();

    toggleDisplay();

    // Re-run the same test.
    // Wait to allow the asynchronous accessibility code that's
    // covered by traceEventsToMeasure to have a chance to run.
    setTimeout(runTest, 2500);
  }
}

function generateAllContent() {
  const root1 = container.appendChild(document.createElement('div'));
  root1.id = 'root1';

  const root2 = container.appendChild(document.createElement('div'));
  root2.id = 'root2';

  for (let i = 0; i < 50; i++) {
    const child1 = generateNodes(12, "blue");
    root1.appendChild(child1);
    const child2 = generateNodes(12, "green");
    root2.appendChild(child2);
  }
}

// Recursively add layers of descendants.
function generateNodes(depth, color) {
  if (depth === 0)
    return;

  const node = document.createElement("div");
  node.className = "child";
  node.style.backgroundColor = color;
  depth--;
  const child = generateNodes(depth, color);
  if(child) {
    node.appendChild(child);
  }
  return node;
}

function toggleDisplay(text) {
  window.hideTop = !window.hideTop;
  document.getElementById("root1").setAttribute('aria-hidden', window.hideTop);
  document.getElementById("root2").setAttribute('aria-hidden', !window.hideTop);
}

PerfTestRunner.startMeasureValuesAsync({
  description: 'Test accessibility performance when toggling display:none/block on large subtrees.',
  unit: 'ms',
  done: function () {
    isDone = true;
  },
  run: function() {
    runTest();
  },
  iterationCount: 6,
  tracingCategories: 'accessibility',
  traceEventsToMeasure: [
    'TotalAccessibilityCleanLayoutLifecycleStages',
    'ProcessDeferredUpdatesLifecycleStage',
    'FinalizingTreeLifecycleStage',
    'SerializeLifecycleStage',
    'RenderAccessibilityImpl::SendPendingAccessibilityEvents',
    'BrowserAccessibilityManager::OnAccessibilityEvents',
    'SerializeLocationChanges',
    "BrowserAccessibilityManager::OnLocationChanges"
  ]
});
</script>

</html>