Before Uber became Public Enemy #1 and prior to the Otto/Levandowski dispute, Google was planning on competing with Uber despite being an investor, which led Kalanick to e-mail David Drummond about it [1]. Drummond eventually left Uber's board (which harkens back to Schmidt leaving Apple's board) but this was well after the relationship had been deteriorating.

[1] http://static4.businessinsider.com/image/595ea97dd9fccd31008...