The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/62508586d4d61e4cad72cfe985413708e90c6969

commit 62508586d4d61e4cad72cfe985413708e90c6969
Author: Elliot Glaysher <erg@chromium.org>
Date: Wed Nov 29 19:18:17 2017

Implement ImmersiveContextMus::OnEnteringOrExitingImmersive().

This changes ash::WindowState to use the aura::Window property that
tracks the same thing instead of storing its own state which gets
updated from the Window.

Bug:  640371 
Change-Id: Ia7d3744844fc21a5f437ecd5376d839933b50c65
Reviewed-on: https://chromium-review.googlesource.com/794831
Commit-Queue: Elliot Glaysher <erg@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520188}
[modify] https://crrev.com/62508586d4d61e4cad72cfe985413708e90c6969/ash/wm/immersive_context_ash.cc
[modify] https://crrev.com/62508586d4d61e4cad72cfe985413708e90c6969/ash/wm/immersive_fullscreen_controller_unittest.cc
[modify] https://crrev.com/62508586d4d61e4cad72cfe985413708e90c6969/ash/wm/tablet_mode/tablet_mode_event_handler.cc
[modify] https://crrev.com/62508586d4d61e4cad72cfe985413708e90c6969/ash/wm/tablet_mode/tablet_mode_window_manager_unittest.cc
[modify] https://crrev.com/62508586d4d61e4cad72cfe985413708e90c6969/ash/wm/window_state.cc
[modify] https://crrev.com/62508586d4d61e4cad72cfe985413708e90c6969/ash/wm/window_state.h
[modify] https://crrev.com/62508586d4d61e4cad72cfe985413708e90c6969/chrome/browser/ui/views/frame/immersive_context_mus.cc