I can't know why there is no public API in the VrVideoView to enter fullscreen mode or VR Split screen mode(Stereoscopic).
I must use the cardboard icon at the bottom left of the view to enter the VR Mode.
I've been able to enter the fullsceen mode by using the bellow code but it ain't same right to me.
If it is still needed. Make sure you have the lastest version ( tested on 0.9.1 )
For fullscreen use
for VR glasses use