This directory should contain non UI Chrome OS specific code that has src/chrome dependencies.
Code here should not contain any ash/ dependencies or chrome/browser/ui dependencies. Any such UI code should be moved to chrome/browser/ui/ash (which may depend on code in this directory).
Example:
The Chrome OS network portal detection model lives in chrome/browser/chromeos/net/network_portal_detector_impl.cc.
The notification controller for network portal detection lives in: chrome/browser/ui/ash/network/network_portal_notification_controller.cc (which depends on chrome/browser/ui, ash/public/cpp/vector_icons/vector_icons.h, and chrome/browser/chromeos/net/network_portal_detector_impl.h.