chromium/chrome/test/data/page_load_metrics/download_anchor_click.html

<html>
<head><title>Download Test</title></head>
<body>
<a id='dl' href="/download-test1.lib">Click to download!</a>
<script>
// Dispatch a click event async, rather than synchronously during parsing,
// since this is consistent with how real user input events are dispatched
// and processed.
window.setTimeout(function() {
  var evt = document.createEvent("MouseEvent");
  evt.initMouseEvent('click', true, true);
  document.getElementById('dl').dispatchEvent(evt);
}, 0);
</script>
</body>
</html>