Google may be looking to get real serious about Virtual Reality. This would be great on their behalf as facebook moves forward with Oculus, Windows continues progress with Holo Lens, and other manufacturers like HTC and Samsung have their own offerings. For now all we have from Google is Google Cardboard.
In the latest version of the Android N Developer Preview we see some mention of VR deep within the system. If you go to Settings, Apps, Configure Apps, Special Access, VR Helper Services you will find "VR Listener" and "VR Helper". The helper services appear to feature a warning related to the VR service. The helper app looks to be able to notify you while you are in VR mode on your Android device.
This should be helpful when using Google Cardboard, Samsung Gear VR, and Project Tango. Maybe Google is secretly working on a VR device of their own. Wouldn't that be sweet!