RELAND - tablet: Fix edge case with |defer_bounds_updates| set inappropriately.

This CL is meant as a low-risk fix of Issue 926602 to merge back to M73.
For the long term, it will be preferable to avoid maximizing windows
before snapping them. Then we might even be able to eliminate
|defer_bounds_updates| altogether (even though it existed before
anything about snapped windows carrying over from desktop to tablet).

  TabletModeControllerTest.DeferBoundsUpdatesForWindowsInOverview*
  TabletModeControllerTest.ProgrammaticallyStartSplitViewAndThenOverview

Test: ash_unittests TabletModeControllerTest.StartTablet*
Test: ash_unittests
Test: ash_unittests
Bug: 926602
Change-Id: I0a068ffae314871c8466d1364bcd96f72b69d345
Reviewed-on: https://chromium-review.googlesource.com/c/1457235
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Commit-Queue: Avery Musbach <amusbach@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#631462}
Reviewed-on: https://chromium-review.googlesource.com/c/1471013
Cr-Commit-Position: refs/heads/master@{#632017}
6 files changed