In a document encouraging Google to fully greenlight the deal with Riot Games, Kochikar wrote:

We pulled all stops (promised them $10M marketing before they signed GVP for example) to get Riot to stop their inhouse “app store” efforts and bring their billion dollar League of Legends franchise and other mobile games to Play (they were most likely to follow Epic’s example). Since then they have pre-registered their games on Play first!

That’s the closest thing we’ve seen yet to Epic’s assertion that Google bribed companies.