Actually I wonder how Facebook's user tracking is actually dealing with mobile users who only use their mobile app. It seems like they'd potentially lose a lot

Actually I wonder how Facebook's user tracking is actually dealing with mobile users who only use their mobile app. It seems like they'd potentially lose a lot of tracking info unless they can track an app login through the mobile browser. I wonder if this is part of the reasoning for their increasing centralization by offering a browser and supposedly actually hosting highly shared content.