I'm not really familiar with the subject, but if Google uses their profit from online advertising to get people to use their phones (by selling them cheaper than "possible"), wouldn't that be the same as Microsoft putting ie in Windows? So what do the anti-competition laws say about this?
No - as far as I understand it, the issue with IE wasn't that Microsoft used profits from Windows to give away IE, it's that they used a monopoly product (Windows) to give an unfair advantage to IE (out-of-the-box distribution not accessible to their competitors).
Actually, the potential issue would be whether they are using profits from one monopoly (search) to undercut competition in another competitive market (mobile phones). A guest post at TechCrunch actually had a good overview of the ways Google might face antitrust action:
