And Android, all of the ad stack, analytics (it gives google a lot of data), chrome, maps, docs, drive (in some form), calendar, app engine, hangouts (part of gmail). There are tons of products that are both successful, and are tied to core things google wants to be good at.
ChromeOS is open sourced and will still be available for some time, but yeah, they're merging the two. Ubiquity between Android and desktop/laptops would be great.