--- a/mobile/android/base/ui/PanZoomController.java
+++ b/mobile/android/base/ui/PanZoomController.java
@@ -407,18 +407,18 @@ public class PanZoomController
             }
         }
 
         mX.updateWithTouchAt(x, timeDelta);
         mY.updateWithTouchAt(y, timeDelta);
     }
 
     private void track(MotionEvent event) {
-        mX.lastTouchPos = mX.touchPos;
-        mY.lastTouchPos = mY.touchPos;
+        mX.saveTouchPos();
+        mY.saveTouchPos();
 
         for (int i = 0; i < event.getHistorySize(); i++) {
             track(event.getHistoricalX(0, i),
                   event.getHistoricalY(0, i),
                   event.getHistoricalEventTime(i));
         }
         track(event.getX(0), event.getY(0), event.getEventTime());
 
@@ -697,18 +697,18 @@ public class PanZoomController
         public enum Overscroll {
             NONE,
             MINUS,      // Overscrolled in the negative direction
             PLUS,       // Overscrolled in the positive direction
             BOTH,       // Overscrolled in both directions (page is zoomed to smaller than screen)
         }
 
         private float firstTouchPos;            /* Position of the first touch event on the current drag. */
-        public float touchPos;                  /* Position of the most recent touch event on the current drag. */
-        public float lastTouchPos;              /* Position of the touch event before touchPos. */
+        private float touchPos;                 /* Position of the most recent touch event on the current drag. */
+        private float lastTouchPos;             /* Position of the touch event before touchPos. */
         public float velocity;                  /* Velocity in this direction. */
         public boolean locked;                  /* Whether movement on this axis is locked. */
         public boolean disableSnap;             /* Whether overscroll snapping is disabled. */
 
         private FlingStates mFlingState;        /* The fling state we're in on this axis. */
 
         public abstract float getOrigin();
         protected abstract float getViewportLength();
@@ -734,16 +734,20 @@ public class PanZoomController
             locked = false;
             firstTouchPos = touchPos = lastTouchPos = pos;
         }
 
         float panDistance(float currentPos) {
             return currentPos - firstTouchPos;
         }
 
+        void saveTouchPos() {
+            lastTouchPos = touchPos;
+        }
+
         void updateWithTouchAt(float pos, float timeDelta) {
             float newVelocity = (touchPos - pos) / timeDelta * MS_PER_FRAME;
 
             // If there's a direction change, or current velocity is very low,
             // allow setting of the velocity outright. Otherwise, use the current
             // velocity and a maximum change factor to set the new velocity.
             boolean curVelocityIsLow = Math.abs(velocity) < 1.0f;
             boolean directionChange = (velocity > 0) != (newVelocity > 0);