AcceleratorProvider: Make GetAcceleratorForCommandId const.

components/translate/core/browser/options_menu_model.h

 // Copyright 2014 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 COMPONENTS_TRANSLATE_CORE_BROWSER_OPTIONS_MENU_MODEL_H_
 #define COMPONENTS_TRANSLATE_CORE_BROWSER_OPTIONS_MENU_MODEL_H_
 
 #include "base/macros.h"
 #include "ui/base/models/simple_menu_model.h"
 
@@ skipping 15 matching lines @@
     REPORT_BAD_DETECTION
   };
 
   explicit OptionsMenuModel(TranslateInfoBarDelegate* translate_delegate);
   ~OptionsMenuModel() override;
 
   // ui::SimpleMenuModel::Delegate implementation:
   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:
   TranslateInfoBarDelegate* translate_infobar_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(OptionsMenuModel);
 };
 
 }  // namespace translate
 
 #endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_OPTIONS_MENU_MODEL_H_