AcceleratorProvider: Make GetAcceleratorForCommandId const.

chrome/browser/renderer_context_menu/open_with_menu_factory_ash.h

 // Copyright 2016 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_RENDERER_CONTEXT_MENU_OPEN_WITH_MENU_FACTORY_ASH_H_
 #define CHROME_BROWSER_RENDERER_CONTEXT_MENU_OPEN_WITH_MENU_FACTORY_ASH_H_
 
 #include <memory>
 #include <unordered_map>
 #include <utility>
@@ skipping 18 matching lines @@
  public:
   using HandlerMap = std::unordered_map<int, ash::LinkHandlerInfo>;
 
   class SubMenuDelegate : public ui::SimpleMenuModel::Delegate {
    public:
     explicit SubMenuDelegate(OpenWithMenuObserver* parent) : parent_(parent) {}
     ~SubMenuDelegate() override {}
 
     bool IsCommandIdChecked(int command_id) const override;
     bool IsCommandIdEnabled(int command_id) const override;
-    bool GetAcceleratorForCommandId(int command_id,
-                                    ui::Accelerator* accelerator) override;
+    bool GetAcceleratorForCommandId(
+        int command_id,
+        ui::Accelerator* accelerator) const override;
     void ExecuteCommand(int command_id, int event_flags) override;
 
    private:
     OpenWithMenuObserver* const parent_;
 
     DISALLOW_COPY_AND_ASSIGN(SubMenuDelegate);
   };
 
   explicit OpenWithMenuObserver(RenderViewContextMenuProxy* proxy);
   ~OpenWithMenuObserver() override;
@@ skipping 37 matching lines @@
   // A menu model received from Ash side.
   std::unique_ptr<ash::LinkHandlerModel> menu_model_;
   OpenWithMenuObserver::HandlerMap handlers_;
   // A submenu passed to Chrome side.
   std::unique_ptr<ui::MenuModel> submenu_;
 
   DISALLOW_COPY_AND_ASSIGN(OpenWithMenuObserver);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_CONTEXT_MENU_OPEN_WITH_MENU_FACTORY_ASH_H_