In the MK6, you can turn them off via the steering wheel controls and navigating through the menu on the MFD (Lights & Convenience / Daytime Running Lights / ON/OFF). It seems only Mk6's after 2011 had this ability. (my MY11.5 Golf R does). I turn my DRL's off on sunny days as i think it looks a bit wanky. I only turn them on if its overcast or a darker day. Engine needs to be running (but not moving, and doors closed) to access the menu on the MFD.

There is also a procedure using the indicator stalk and ignition which works on my 2010 GTI. Push indicator down (as if turning left) and pull towards you (as if indicating to turn left and also using the highbeams) and then turn the ignition on. Hold for 5 seconds and beep will sound and DRL's will turn off.

To turn them back on, repeat the same process but indicate right.

Surely the MK7 will be similar to one of these processes.