v1-mutate-deep-tree-then-slot-flatten.html

<!DOCTYPE html>
<html>
<head>
  <script type="text/javascript" src="../resources/runner.js"></script>
  <script type="text/javascript" src="./v1-common.js"></script>
</head>
<body>
<div id="parent"></div>

<script>
const deepNestLevel = 50;
const loop = 100;

let host;
let deepSlot;

PerfTestRunner.measureTime({
  description: `Measure distribution`,
  setup: () => {
    host = createDeepComponent(deepNestLevel);
    document.querySelector('#parent').appendChild(host);
    deepSlot = GetDeepestFirstChild(host).querySelector('slot');
    document.body.offsetLeft;
  },
  run: () => {
    for (let i = 0; i < loop; ++i) {
      rotateChildren(deepSlot.parentNode);
      deepSlot.assignedNodes({ flatten: true });
    }
  },
  teardown: () => {
    host.remove();
  }
});
</script>
</body>
</html>

chromium/third_party/blink/perf_tests/shadow_dom/v1-mutate-deep-tree-then-slot-flatten.html