Why not just place a product manager above each product (Gmail, YouTube, Play Music, etc. etc.) that each report to the master manager who's only job is basically to unify all the services and make them work together in a nice way. He would be the one to force everyone to use the same animations, same icons, same conventions etc.. honestly I never understand how companies with millions of dollars can't come up with the simple fix of 'give an experienced person total authority'.