Mobile VR headsets: hardware or software?
Look at the teardown of the two devices:

Gear VR - contains circuitry for the capacitive touchpad on it, plus sensors for detecting if the user is present and USB for connecting it with the phone (presumably to send/receive the above 2 signals).

Daydream View - same for the touchpad, plus NFC chips for one-touch pairing with the phone, and Bluetooth for communication with the Daydream controller.

Gear VR is co-developed with Oculus and thus bears their mark.