public void setDragScrollProfile(DragScrollProfile ssp) {
        if (ssp != null) {
            mScrollProfile = ssp;
        }
    }
Completely custom scroll speed profile. Default increases linearly
with position and is constant in time. Create your own by implementing
{@link DragSortListView.DragScrollProfile}.

@param ssp
third_party/DragSortListView/src/com/mobeta/android/dslv/DragSortListView.java