AcceleratorProvider: Make GetAcceleratorForCommandId const.

chrome/browser/ui/ash/launcher/launcher_application_menu_item_model.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_UI_ASH_LAUNCHER_LAUNCHER_APPLICATION_MENU_ITEM_MODEL_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_LAUNCHER_APPLICATION_MENU_ITEM_MODEL_H_
 
 #include <memory>
 
 #include "ash/common/shelf/shelf_menu_model.h"
@@ skipping 15 matching lines @@
       ChromeLauncherAppMenuItems item_list);
   ~LauncherApplicationMenuItemModel() override;
 
   // Overridden from ash::ShelfMenuModel:
   bool IsCommandActive(int command_id) const override;
 
   // Overridden from ui::SimpleMenuModel::Delegate:
   bool IsCommandIdChecked(int command_id) const override;
   bool IsCommandIdEnabled(int command_id) const override;
   bool GetAcceleratorForCommandId(int command_id,
-                                  ui::Accelerator* accelerator) override;
+                                  ui::Accelerator* accelerator) const override;
   void ExecuteCommand(int command_id, int event_flags) override;
 
  private:
   friend class LauncherApplicationMenuItemModelTestAPI;
 
   void Build();
 
   // Returns the number of menu items that are enabled.
   int GetNumMenuItemsEnabled() const;
 
   // Records UMA metrics when a menu item is selected.
   void RecordMenuItemSelectedMetrics(int command_id,
                                      int num_menu_items_enabled);
 
   // The list of menu items as returned from the launcher controller.
   ChromeLauncherAppMenuItems launcher_items_;
 
   DISALLOW_COPY_AND_ASSIGN(LauncherApplicationMenuItemModel);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_LAUNCHER_APPLICATION_MENU_ITEM_MODEL_H_