chromeos: Show deprecated accelerator notifications in mash

ash/mus/accelerators/accelerator_controller_delegate_mus.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/mus/accelerators/accelerator_controller_delegate_mus.h"
 
 #include "ash/mus/window_manager.h"
 #include "base/logging.h"
 #include "mash/public/interfaces/launchable.mojom.h"
 #include "services/service_manager/public/cpp/connector.h"
@@ skipping 127 matching lines @@
       window_manager_->connector()->BindInterface("touch_hud", &launchable);
       launchable->Launch(mash::mojom::kWindow,
                          mash::mojom::LaunchMode::DEFAULT);
       break;
     }
     default:
       NOTREACHED();
   }
 }
 
-void AcceleratorControllerDelegateMus::ShowDeprecatedAcceleratorNotification(
-    const char* const notification_id,
-    int message_id,
-    int old_shortcut_id,
-    int new_shortcut_id) {
-  // TODO: http://crbug.com/630316.
-  NOTIMPLEMENTED();
-}
-
 }  // namespace mus
 }  // namespace ash