base

Notify native that scrolling has stopped correctly

bug:5255022
bug:5218838

When the view starts scrolling, we tell native so it can block updates until the
view stops scrolling. This change fixes an issue where wouldn't tell native that
we stopped scrolling because the view didn't have room to move.

Change-Id: I5f2eec31493570937f7b8b2992a85283de06fb60