Touch, wake and unlock

- Add onFingerprintAcquired, so Keyguard can grab a wakelock to prevent
the device from sleeping.
- If we get a successful fingerprint, wake the device up, immediately
dismiss the keyguard and tell PWM that we kicked off our frame that
will represent the correct state.
- PWM then waits for this frame to be drawn, and then turns on the
screen, which results in unlocking directly to the previsouly
opened app.

Bug: 21855614
Change-Id: I5f43df17fa5e4e9c6a6392eef4a4590b07df4f96