AcceleratorProvider: Make GetAcceleratorForCommandId const.

ui/message_center/message_center_tray.cc

 // Copyright (c) 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.
 
 #include "ui/message_center/message_center_tray.h"
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/observer_list.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 23 matching lines @@
  public:
   NotificationMenuModel(MessageCenterTray* tray,
                         const NotifierId& notifier_id,
                         const base::string16& display_source);
   ~NotificationMenuModel() 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:
   MessageCenterTray* tray_;
   NotifierId notifier_id_;
   DISALLOW_COPY_AND_ASSIGN(NotificationMenuModel);
 };
 
 NotificationMenuModel::NotificationMenuModel(
     MessageCenterTray* tray,
@@ skipping 21 matching lines @@
 bool NotificationMenuModel::IsCommandIdChecked(int command_id) const {
   return false;
 }
 
 bool NotificationMenuModel::IsCommandIdEnabled(int command_id) const {
   return tray_->delegate()->IsContextMenuEnabled();
 }
 
 bool NotificationMenuModel::GetAcceleratorForCommandId(
     int command_id,
-    ui::Accelerator* accelerator) {
+    ui::Accelerator* accelerator) const {
   return false;
 }
 
 void NotificationMenuModel::ExecuteCommand(int command_id, int event_flags) {
   switch (command_id) {
     case kTogglePermissionCommand:
       tray_->message_center()->DisableNotificationsByNotifier(notifier_id_);
       break;
 #ifdef OS_CHROMEOS
     case kShowSettingsCommand:
@@ skipping 170 matching lines @@
     ShowPopupBubble();
 
   NotifyMessageCenterTrayChanged();
 }
 
 void MessageCenterTray::NotifyMessageCenterTrayChanged() {
   delegate_->OnMessageCenterTrayChanged();
 }
 
 }  // namespace message_center