The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8b25d2d0aa00b1b62328f726f3ae929348b9e6d5

commit 8b25d2d0aa00b1b62328f726f3ae929348b9e6d5
Author: Yunfan Chen <yunfanc@google.com>
Date: Fri Jun 08 07:44:23 2018

Correct snapped window state change reason

This change overrides the bounds change reason to be snapped over
drag_move. Otherwise, when drag a window into snapped mode, the
drag to reposition reason will override the snap reason for bound
change. The server will then send the incorrect reason to ARC++ side.

With this change, ARC++ N and P will correctly turn into snapped mode
when drag a window to side.

Bug:  848626 
Change-Id: I0174ea36166ad378f2ba6d935d3ab32b5ece98ae
Reviewed-on: https://chromium-review.googlesource.com/1084574
Commit-Queue: Yunfan Chen <yunfanc@chromium.org>
Reviewed-by: Stefan Kuhne <skuhne@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: David Reveman <reveman@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565577}
[modify] https://crrev.com/8b25d2d0aa00b1b62328f726f3ae929348b9e6d5/components/exo/wayland/server.cc