Adding GestureObserver for the gesture detection mechanism. Bug: 149269335 Test: GesturesObserverTest, SimpleSwipeTest, TwoFingersDownTest Change-Id: I052ede9ec0698c9811a6cf2b2a13333a313b2943
Adding GestureObserver for the gesture detection mechanism. Bug: 149269335 Test: GesturesObserverTest, SimpleSwipeTest, TwoFingersDownTest Change-Id: I052ede9ec0698c9811a6cf2b2a13333a313b2943