function updatePointerCancel( tracker, eventInfo, gPoint ) {
        var pointsList = tracker.getActivePointersListByType( gPoint.type ),
            updateGPoint;

        updateGPoint = pointsList.getById( gPoint.id );

        if ( updateGPoint ) {
            stopTrackingPointer( tracker, pointsList, updateGPoint );
        }
    }
@function
@private
@inner
@param {OpenSeadragon.MouseTracker} tracker
    A reference to the MouseTracker instance.
@param {OpenSeadragon.MouseTracker.EventProcessInfo} eventInfo
    Processing info for originating DOM event.
@param {OpenSeadragon.MouseTracker.GesturePoint} gPoint
     Gesture points associated with the event.