This might provide some insight:

moxie0 MoxieSignal Staff Aug '17

I think there’s an issue for this already, but if you write and maintain a place picker library which doesn’t use Google >Maps that’s API compatible with the one from play services, we could look at including it.

https://community.signalusers.org/t/share-location-without-gapps-on-android-phone/1246/2