A means to emit geolocation positions

It would be great if Web Driver provided a means for a user agent to emit a Geolocation coordinates. These would be picked up by the Geolocation API's requestPosition() and watchPosition() methods.

This would be beneficial to both web developers and implementers.

The straw person is to allow developers to pass an JSON object with a shape that matches GeolocationCoordinates.

Then the UA can just echo that as a real GeolocationCoordinates object.

On WPT, at least, (and yes, I'm aware test_driver is not part of this spec.. just showing it as a use case) I'm imagining something like:

await test_driver.set_permission({"name": "geolocation"}, "granted");
const positionPromise = new Promise((res, rej) => navigator.geolocation.getCurrentPosition(res, rej));
await test_driver.emit_geo_position({ latitude: -37, longitude: 100 });
const position = await positionPromise; 

Similarly, with watchPosition(), one would get the 3 positions:

navigator.geolocation.watchPosition(console.log);
await test_driver.emit_geo_position({ latitude: 37, longitude: 100 });
await test_driver.emit_geo_position({ latitude: 36, longitude: 100 });
await test_driver.emit_geo_position({ latitude: 35, longitude: 100 });

Thoughts?

Start by reviewing the WebDriver issue's proposed JSON shape and the example calls to test_driver.emit_geo_position, alongside the Geolocation API methods named there. Compare the desired behavior for getCurrentPosition() and watchPosition(), then determine the specification changes and tests needed to demonstrate that supplied positions are delivered to both callbacks.