I am very skeptical of partnership between google and coinbase because big companies like google/facebook like to buy the companies instead of doing JV's with them. Alternatively Google might come up with their own services as they have massive user base and technical expertise.
Totally agree with this opinion, Google has lot of money, and instead of doing an MoU they will prefer to make an acquisition, but however, I don't think any of those scenarios will happen in the near future. Google is still sceptical toward cryptocurrency, they might start to approaching blockchain technology, but not cryptocurrency. In the last years, they keep restricting many crypto activities in most of their platform and service.