chromium/third_party/blink/perf_tests/layout/line-layout-fit-content.html

<!DOCTYPE html>
<script src="../resources/runner.js"></script>
<script src="resources/line-layout-perf-test.js"></script>
<style>
#parent {
  width: 400px;
}
#container {
  width: fit-content;
}
</style>
<body onload="run()">
<div id="parent">
  <div id="container"></div>
</div>
<script>
'use strict';

function run() {
  var test = new LineLayoutPerfTest(container);
  test.lineCount = 10000;
  test.run('Measures performance of "width: fit-content" of long text.');
}
</script>
</body>