I believe that at some point in the future they will launch a joint-venture for a fully automated Uber competitor with Tesla handling designing and building the vehicles and Google providing cash, self-driving software and building the actual app.

Musk is literally too good friends with Sergey Brin and Larry Page for this not too happen.

http://motherboard.vice.com/read/elon-musk-and-larry-page-ha...

http://www.businessinsider.com/googles-secret-apartment-elon...