fuchsia/engine/test/data/mic.html

<script>
  function callGetUserMedia(haveAccess) {
    return navigator.mediaDevices.getUserMedia({ audio: true, video: false })
      .then(() => {
        if (!haveAccess) {
          throw "getUserMedia() succeeded when the page doesn't have " +
                "micriphone access";
        }
      })
      .catch((e) => {
        if (!haveAccess && e.name == "NotFoundError")
          return;
        throw e;
      });
  }

  function callEnumerateDevices(haveAccess) {
    return navigator.mediaDevices.enumerateDevices().then((devices)=>{
      var found = false;
      for (d of devices) {
        if (d.kind == "audioinput") {
          found = true;
          if (d.deviceId == "" && haveAccess) {
            throw "deviceId must not be empty when mic permission is granted.";
          } else if (d.deviceId != "" && !haveAccess) {
            throw "deviceId must be non-empty only when mic permission is granted.";
          }
          if (d.label != "" && !haveAccess) {
            throw "device label must be empty unless mic permission is granted.";
          }
          // TODO(crbug.com/1065436): Verify that d.label is set when microphone
          // permission is granted.
        }
      }
      if (!found) {
        throw "enumerateDevices() didn't return any audioinput devices.";
      }
    });
  }

  // NoPermission is passed in the URL when the page doesn't have microphone
  // access.
  var haveAccess = (window.location.href.indexOf("NoPermission") < 0);

  callGetUserMedia(haveAccess)
  .then(() => { return callEnumerateDevices(haveAccess); })
  .then(() => { document.title = "ended"; })
</script>