Log the following lockscreen gestures:
* Swipe up to unlock
* Swipe down to enter full shade
* Tap in empty area (causing unlock hint)
* Swipe to camera
* Swipe to dialer
* Tap on lock to lock device
* Tap on notification, activating it
For swipe gestures, includes length and velocity where available.
Bug: 18767135
Change-Id: Ib2c535e3a9d2b378f5a2a0a00c2be3fd916554ac
