GitLab

This CL fixes the ash add/remove display accelerators when running with
--mus. When the accelerator is pressed it needs to call
TestDisplayController::AddRemoveDisplay(). The TestDisplayControllerPtr
is moved into DisplayManager to simplify things. This allows removing
the special case for the DEV_ADD_REMOVE_DISPLAY accelerator.

Both --mus and --mash will set TestDisplayControllerPtr on startup if
they are running on Linux desktop. It would be possible to do something
similar with classic ash in the future.

Bug: 779845
Change-Id: I70b058777944217e55ef105b9d1ac65f05e28b3a
Reviewed-on: https://chromium-review.googlesource.com/746375Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512996}