chromium/chrome/test/data/speech/web_speech_test.html

<!doctype html>
<body>
<script>
window.results = null;

window.getFirstTranscript = function() {
  var rs = window.results;
  if (!rs || !rs.length) { return 'NOTFOUND'; }
  var r = rs[0];
  if (!r.length) { return 'NOTFOUND'; }
  return r.item(0).transcript;
};

window.testSpeechRecognition = function() {
  var reco = new webkitSpeechRecognition();
  reco.continuous = true;
  reco.onresult = function(e) {
    try {
      document.title = 'PASS';
      window.results = e.results;
    } catch(ex) {
      document.title = 'FAIL';
    }
  }
  reco.onerror = function(e) {
    document.title = 'FAIL';
  }
  try {
    reco.start();
  } catch(e) {
    document.title = 'FAIL';
  }
};
</script>
</body>