Omri, what's the expected behavior here? 
If one side of the screen is occupied by a snapped window, and the other side is overview grid, and if the snapped window has a minimal size, can the user drag the divider to pass over the minimal bounds line to close the snapped window? Or we should not allow that? 

Beyond the minimum bounds of the window it starts doing the fade-out animation (darkening app and minimizing viewable area as you drag) towards closing the app.

Ben, please correct me if I'm wrong.

That sounds right to me.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8bfcbd34dee3edc1f2a6fbb07d5682023dfa32b0

commit 8bfcbd34dee3edc1f2a6fbb07d5682023dfa32b0
Author: MinChen <minch@chromium.org>
Date: Wed Nov 01 02:40:04 2017

Allowing the snapped window can be moved outside of work area.

Changes:
1. Allowing the snapped window that next to the origin of the work area
   can be moved outside of the bounds of work area.
2. Delete RestackWindows in SplitViewController, since left and right
   snapped window will not overlap now.

Bug:  775236 
Change-Id: Ib1d12443f8b9965544014590b8eff37ed8b3f665
Reviewed-on: https://chromium-review.googlesource.com/741489
Commit-Queue: min c <minch@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513052}
[modify] https://crrev.com/8bfcbd34dee3edc1f2a6fbb07d5682023dfa32b0/ash/wm/splitview/split_view_controller.cc
[modify] https://crrev.com/8bfcbd34dee3edc1f2a6fbb07d5682023dfa32b0/ash/wm/splitview/split_view_controller.h
[modify] https://crrev.com/8bfcbd34dee3edc1f2a6fbb07d5682023dfa32b0/ash/wm/splitview/split_view_controller_unittest.cc