That's a misunderstanding of the Microsoft situation. The antitrust issue in that case was tying: http://en.wikipedia.org/wiki/Tying_(commerce)

With the notable exception of Google+ (which has now been relaxed), signing up for one google service did not force you into any other google service or product. You can access any google property on IE or other browsers. There is no anti-competitive compulsion in the way that Microsoft forces IE upon windows customers.