Microsoft is behind it at least in the EU probe. I would surprised if they had nothing to do with US probe as well.
That aside if the whole idea for the probe is that Google prefers their own services on Android while restricting others - it's going to be a tough one to substantiate given Microsoft already can ship all of their apps as replacement to Google's - Cortana for example.
If Antitrust wasn't just about market share but also profit share then Apple is doing far more to invite a probe than Google in the Smart Phone market.
That aside if the whole idea for the probe is that Google prefers their own services on Android while restricting others - it's going to be a tough one to substantiate given Microsoft already can ship all of their apps as replacement to Google's - Cortana for example.
If Antitrust wasn't just about market share but also profit share then Apple is doing far more to invite a probe than Google in the Smart Phone market.