Add service name constant for UI service.

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"
+#include "services/ui/public/interfaces/constants.mojom.h"
 #include "services/ui/public/interfaces/display/display_controller.mojom.h"
 #include "services/ui/public/interfaces/display/test_display_controller.mojom.h"
 
 namespace ash {
 namespace mus {
 
 AcceleratorControllerDelegateMus::AcceleratorControllerDelegateMus(
     WindowManager* window_manager)
     : window_manager_(window_manager) {
 #if !defined(OS_CHROMEOS)
@@ skipping 74 matching lines @@
 }
 
 void AcceleratorControllerDelegateMus::PerformAction(
     AcceleratorAction action,
     const ui::Accelerator& accelerator) {
 #if defined(OS_CHROMEOS)
   switch (action) {
     case DEV_ADD_REMOVE_DISPLAY: {
       display::mojom::TestDisplayControllerPtr test_display_controller;
       window_manager_->connector()->ConnectToInterface(
-          "ui", &test_display_controller);
+          ui::mojom::kServiceName, &test_display_controller);
       test_display_controller->ToggleAddRemoveDisplay();
       break;
     }
     case DEV_TOGGLE_UNIFIED_DESKTOP: {
       // TODO(crbug.com/657816): This is hack. I'm just stealing the shortcut
       // key to toggle display size in mus. This should be removed by launch.
       display::mojom::TestDisplayControllerPtr test_display_controller;
       window_manager_->connector()->ConnectToInterface(
-          "ui", &test_display_controller);
+          ui::mojom::kServiceName, &test_display_controller);
       test_display_controller->ToggleDisplayResolution();
       break;
     }
     case SWAP_PRIMARY_DISPLAY: {
       window_manager_->GetDisplayController()->SwapPrimaryDisplay();
       break;
     }
     case TOUCH_HUD_PROJECTION_TOGGLE: {
       mash::mojom::LaunchablePtr launchable;
       window_manager_->connector()->ConnectToInterface("touch_hud",
@@ skipping 14 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