The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0a064b94c18ee6d1d251c8d381aa8c22372e6248

commit 0a064b94c18ee6d1d251c8d381aa8c22372e6248
Author: sadrul <sadrul@chromium.org>
Date: Fri Apr 22 17:36:50 2016

mash/wm: Fix detecting container windows.

Now that not all container windows are direct children of the root window, it is
necessary to consult the RootWindowController to find the container windows.
Also, instead of checking whether a direct child of the root, RootWindowController
needs to look at the local-id of a window to determine whether it's a container
window or not.

BUG= 605668 

Review URL: https://codereview.chromium.org/1907153002

Cr-Commit-Position: refs/heads/master@{#389152}

[modify] https://crrev.com/0a064b94c18ee6d1d251c8d381aa8c22372e6248/mash/wm/BUILD.gn
[add] https://crrev.com/0a064b94c18ee6d1d251c8d381aa8c22372e6248/mash/wm/disconnected_app_handler.cc
[add] https://crrev.com/0a064b94c18ee6d1d251c8d381aa8c22372e6248/mash/wm/disconnected_app_handler.h
[modify] https://crrev.com/0a064b94c18ee6d1d251c8d381aa8c22372e6248/mash/wm/root_window_controller.cc
[modify] https://crrev.com/0a064b94c18ee6d1d251c8d381aa8c22372e6248/mash/wm/window_manager.cc
[modify] https://crrev.com/0a064b94c18ee6d1d251c8d381aa8c22372e6248/mash/wm/window_manager.h
[modify] https://crrev.com/0a064b94c18ee6d1d251c8d381aa8c22372e6248/mash/wm/window_manager_unittest.cc

Bulk verified