Two small ash fixes.

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 "base/logging.h"
 #include "mash/public/interfaces/launchable.mojom.h"
 #include "services/ui/public/interfaces/display/display_controller.mojom.h"
 
@@ skipping 37 matching lines @@
     case TAKE_WINDOW_SCREENSHOT:
     case UNPIN:
       NOTIMPLEMENTED();
       return false;
 
 #if defined(OS_CHROMEOS)
     case DEV_ADD_REMOVE_DISPLAY: {
       display::mojom::DisplayControllerPtr display_controller;
       connector_->ConnectToInterface("mojo:ui", &display_controller);
       display_controller->ToggleVirtualDisplay();
-      break;
+      return true;
     }
     case DEV_TOGGLE_UNIFIED_DESKTOP:
     case DISABLE_GPU_WATCHDOG:
     case LOCK_PRESSED:
     case LOCK_RELEASED:
     case POWER_PRESSED:
     case POWER_RELEASED:
     case SWAP_PRIMARY_DISPLAY:
     case TOGGLE_MIRROR_MODE:
     case TOUCH_HUD_CLEAR:
@@ skipping 33 matching lines @@
     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