In general product management does what you might think of "brand management" and "design language" so if Android needed roundier iconography I expect Barra was the guy to sign off on that, or if Samsung was getting too aggressive in making it a "Galaxy" phone instead of an "Android" phone he might get involved in that. I don't have inside knowledge, its just the kinds of things that role does in tech companies. That is why I wouldn't expect to see any sort of explicit impact statements wrt to Android. Rubin leaving on the other hand suggested that Android was going to become less the lede and more the flavor. Google has spent a lot of effort on making "Chrome" a more inclusive brand than Android which I find fascinating from a strategy perspective.