Remove extension-to-component migration mechanism

chrome/browser/ui/toolbar/media_router_contextual_menu.h

 // Copyright 2015 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_TOOLBAR_MEDIA_ROUTER_CONTEXTUAL_MENU_H_
 #define CHROME_BROWSER_UI_TOOLBAR_MEDIA_ROUTER_CONTEXTUAL_MENU_H_
 
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/base/models/simple_menu_model.h"
 
 class Browser;
 
-namespace extensions {
-class ComponentMigrationHelper;
-}  // namespace extensions
-
 // The class for the contextual menu for the Media Router action.
 class MediaRouterContextualMenu : public ui::SimpleMenuModel::Delegate {
  public:
   explicit MediaRouterContextualMenu(Browser* browser);
 
   // Constructor for injecting values in tests.
   MediaRouterContextualMenu(Browser* browser, bool shown_by_policy);
   ~MediaRouterContextualMenu() override;
 
   ui::MenuModel* menu_model() { return &menu_model_; }
@@ skipping 13 matching lines @@
   // ui::SimpleMenuModel::Delegate:
   bool IsCommandIdChecked(int command_id) const override;
   bool IsCommandIdEnabled(int command_id) const override;
   bool IsCommandIdVisible(int command_id) const override;
   void ExecuteCommand(int command_id, int event_flags) override;
 
   void ReportIssue();
 
   Browser* const browser_;
   ui::SimpleMenuModel menu_model_;
-  extensions::ComponentMigrationHelper* const component_migration_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaRouterContextualMenu);
 };
 
 #endif  // CHROME_BROWSER_UI_TOOLBAR_MEDIA_ROUTER_CONTEXTUAL_MENU_H_