I'm not a lawyer, but I don't think it's "bundling" when you add features to your product. The contention in the Microsoft case was that they forced OEMs to "bundle" IE and block Netscape.

There is also the small matter of Google being free, and the lack of any meaningful lock-ins (this being the web and all) and the matter of Facebook being the leading social network, and other such subtleties that make these cases very dissimilar.

There is also the discussion of whether or not the DOJ was wise in pursuing that case which they subsequently lost, seeing as last I checked IE still ships with Windows.