Migrate (Network)ErrorScreen to ScreenContext

chrome/browser/ui/webui/chromeos/login/update_screen_handler.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_WEBUI_CHROMEOS_LOGIN_UPDATE_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_UPDATE_SCREEN_HANDLER_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 16 matching lines @@
   void Hide() override;
   void Bind(UpdateModel& model) override;
   void Unbind() override;
 
   // BaseScreenHandler:
   void DeclareLocalizedValues(
       ::login::LocalizedValuesBuilder* builder) override;
   void Initialize() override;
 
  private:
+  // Observer is added in OobeUI.
   // NetworkDropdownHandler::Observer implementation:
   void OnConnectToNetworkRequested() override;
 
   UpdateModel* model_;
 
   // Keeps whether screen should be shown right after initialization.
   bool show_on_init_;
 
   DISALLOW_COPY_AND_ASSIGN(UpdateScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_UPDATE_SCREEN_HANDLER_H_