The problem is if google treats the chrome affiliate junk content differently from other junk content. If it is all treated the same, then it should be ok.

I imagine that Google's search algo team is in a separate silo from their chrome marketing team (much like the search algo team is separated from the Adsense team) to try isolate them from the corrupting influence of their marketing team.

That said, Google would be risking their search cash cow by the mere existence of this sort of campaign as it undermines the perception of the independence of their search results, so perhaps they should steer clear of offering incentives of this sort.