Again, Firefox is open source.Chrome isn't, but what it's based off of (Chromium) is, meaning that Google can add the usage tracking features into Chromium's source code before making it proprietary software and releasing it under "Chrome". In fact, that's exactly what they do.
Internet browser argument:GO!
Would you no longer bank if I told you that the government keeps track of every deposit and withdrawal and what you buy with your withdrawals?