Adding logging for the ML mBack gesture model.

Test: manual on device
Bug:150170384
Change-Id: Id6e71b806db3e7cc8bf0b98321c561a5d2e8fbca
Merged-In: Id6e71b806db3e7cc8bf0b98321c561a5d2e8fbca
(cherry picked from commit 6f83f477b9b44a4511f0bc817233a23b76be3654)
1 file changed