AcceleratorProvider: Make GetAcceleratorForCommandId const.

chrome/browser/ui/views/frame/system_menu_model_delegate.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_VIEWS_FRAME_SYSTEM_MENU_MODEL_DELEGATE_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_SYSTEM_MENU_MODEL_DELEGATE_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "chrome/browser/ui/browser.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/models/simple_menu_model.h"
 
 // Provides the SimpleMenuModel::Delegate implementation for system context
 // menus.
 class SystemMenuModelDelegate : public ui::SimpleMenuModel::Delegate {
  public:
   SystemMenuModelDelegate(ui::AcceleratorProvider* provider, Browser* browser);
   ~SystemMenuModelDelegate() override;
 
   Browser* browser() { return browser_; }
 
   // 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;
   bool IsItemForCommandIdDynamic(int command_id) const override;
   base::string16 GetLabelForCommandId(int command_id) const override;
   void ExecuteCommand(int command_id, int event_flags) override;
 
  private:
   ui::AcceleratorProvider* provider_;  // weak
   Browser* browser_;  // weak
 
   DISALLOW_COPY_AND_ASSIGN(SystemMenuModelDelegate);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_SYSTEM_MENU_MODEL_DELEGATE_H_