So, their browser on their operating system has features which only work with their search engine. How does this not violate antitrust laws? Product tying, at the least?
Because you can choose a different phone OS, and you can choose a different browser on that OS. Also, both of those things are open source so you can fork them if you want. How do you think it violates antitrust laws? Do you propose that all companies should be required to make all of their features available on all possible variational usage of their service?
Also you should put quotes around open-source, AOSP does not run on any real device due to a lot of android parts being private + private drivers. It took me one month to run a custom kernel on my Samsung to get the basic hardware working, it's as far as open source as you can get. Android is a "look but don't touch" kind of open-source.