Fix issue with flashing on overscroll

- Apply the bounded current scroll to the overscroll instead of assuming
  the max scroll (on the last tick, the overscroll amount can be zero,
  causing us to shift to the max scroll until the next draw)

Bug: 126767319
Change-Id: Ia60ecb0c3f18e68d0c91620aa79b21df72c213cf
1 file changed