Remove the unused variable.

Test: manual
Bug: 148104018
Change-Id: I15e7b75ae8f0a2945f9917381acc64528f867283

packages/SystemUI/src/com/android/systemui/statusbar/phone/EdgeBackGestureHandler.java

@@ -110,8 +110,6 @@ public class EdgeBackGestureHandler implements DisplayListener,
     private final float mTouchSlop;
     // Duration after which we consider the event as longpress.
     private final int mLongPressTimeout;
-    // The back gesture type
-    private int mBackType;
 
     private final PointF mDownPoint = new PointF();
     private final PointF mEndPoint = new PointF();