Doing this as part of some accelerator cleanup, https://codereview.chromium.org/2748173002

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/84583c03bdaa1f2070997c4e1a17f4c97639bcec

commit 84583c03bdaa1f2070997c4e1a17f4c97639bcec
Author: jamescook <jamescook@chromium.org>
Date: Tue Mar 14 21:05:31 2017

chromeos: Show deprecated accelerator notifications in mash

Now that we support mus-aura the code just needed to be moved back to the
common accelerator controller. This helps clean up
AcceleratorControllerDelegate.

No functional changes.

BUG= 630316 
TEST=ash_unittests, Shift-Esc shows deprecated accelerator notification

Review-Url: https://codereview.chromium.org/2748173002
Cr-Commit-Position: refs/heads/master@{#456827}

[modify] https://crrev.com/84583c03bdaa1f2070997c4e1a17f4c97639bcec/ash/accelerators/accelerator_controller_delegate_aura.cc
[modify] https://crrev.com/84583c03bdaa1f2070997c4e1a17f4c97639bcec/ash/accelerators/accelerator_controller_delegate_aura.h
[modify] https://crrev.com/84583c03bdaa1f2070997c4e1a17f4c97639bcec/ash/common/accelerators/accelerator_controller.cc
[modify] https://crrev.com/84583c03bdaa1f2070997c4e1a17f4c97639bcec/ash/common/accelerators/accelerator_controller_delegate.h
[modify] https://crrev.com/84583c03bdaa1f2070997c4e1a17f4c97639bcec/ash/mus/accelerators/accelerator_controller_delegate_mus.cc
[modify] https://crrev.com/84583c03bdaa1f2070997c4e1a17f4c97639bcec/ash/mus/accelerators/accelerator_controller_delegate_mus.h