AcceleratorProvider: Make GetAcceleratorForCommandId const.

chrome/browser/ui/content_settings/content_setting_media_menu_model.h

 // Copyright 2013 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_CONTENT_SETTINGS_CONTENT_SETTING_MEDIA_MENU_MODEL_H_
 #define CHROME_BROWSER_UI_CONTENT_SETTINGS_CONTENT_SETTING_MEDIA_MENU_MODEL_H_
 
 #include <map>
 
 #include "base/callback.h"
@@ skipping 17 matching lines @@
   ContentSettingMediaMenuModel(
       content::MediaStreamType type,
       ContentSettingBubbleModel* bubble_model,
       const MenuLabelChangedCallback& callback);
   ~ContentSettingMediaMenuModel() override;
 
   // 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:
   typedef std::map<int, content::MediaStreamDevice> CommandMap;
 
   content::MediaStreamType type_;
   ContentSettingBubbleModel* media_bubble_model_;  // Weak.
   MenuLabelChangedCallback callback_;
   CommandMap commands_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentSettingMediaMenuModel);
 };
 
 #endif  // CHROME_BROWSER_UI_CONTENT_SETTINGS_CONTENT_SETTING_MEDIA_MENU_MODEL_H_