Why would game industry veteran Phil Harrison join Google?

Phil Harrison, a veteran of Sony and Microsoft’s game console businesses, tweeted today that he had taken a job at Google. That’s a big development in the game business, and it raises the question about why Google would hire Harrison as the vice president and general manager of a mysterious new business.Excited to be able to share that today I've started a new role as Vice President and GM of Google – and relocating (back) to California.
— Phil Harrison (@MrPhilHarrison)