chromium/third_party/blink/web_tests/wpt_internal/speech/scripted/speechrecognition-re-restart.html

<!doctype html>
<title>Verify that multiple overlapping start() calls is well-behaved.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script type="module">
import {MockSpeechRecognizer} from '../resources/mock-speechrecognizer.js';

const mock = new MockSpeechRecognizer();

async_test(t => {
  const r1 = new webkitSpeechRecognition();
  r1.onend = () => r1.start();
  r1.start();

  const r2 = new webkitSpeechRecognition();
  r2.onend = () => setTimeout(() => t.done());
  r2.start();
});

</script>