chromium/third_party/blink/web_tests/wpt_internal/geolocation-api/resources/window-close-popup.html

<script type="module">
import {GeolocationMock} from './geolocation-mock.js';

const mockLatitude = 51.478;
const mockLongitude = -0.166;
const mockAccuracy = 100.0;

window.loadNext = () => {
    const mock = new GeolocationMock();
    mock.setGeolocationPermission(true);
    mock.setGeolocationPosition(mockLatitude, mockLongitude, mockAccuracy);

    navigator.geolocation.watchPosition(window.opener.gotPosition);
}
</script>
<body onload="loadNext()"></body>