GitLab

This CL:
* Moves a bunch of related DisplayManager and DisplayConfigurator
  code to a separate InitializeDisplayManager method to help improve
  managability of Shell::Init.
* Renames ShutdownObserver -> DisplayShutdownObserver.
* Removes unnecessary DBusThreadManager dependencies from shell.cc.
* Moves observer responsibility from Shell to ProjectingObserver

Bug: 678949
Change-Id: I07159d0562bc032f03c653beb927ab8aaf053bbc
Reviewed-on: https://chromium-review.googlesource.com/833500Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526741}