Carry over snapped windows from laptop to tablet.

If the active window is snapped when the user switches from laptop mode
to tablet mode, then split view shall be activated with the active
window on the side to which it was snapped. On the other side shall be
the previous window if it was snapped to that side, and overview
otherwise.

Bug: 819798
Change-Id: I22830563e0fea71977cd5b6c0b78f9d4f3a66e71
Reviewed-on: https://chromium-review.googlesource.com/c/1391470
Commit-Queue: Avery Musbach <amusbach@google.com>
Reviewed-by: Stefan Kuhne <skuhne@chromium.org>
Reviewed-by: Jenny Zhang <jennyz@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619459}
5 files changed