cros: Disable system tray help/lock buttons during supervised user creation

ash/system/tiles/tiles_default_view.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 ASH_SYSTEM_TILES_TILES_DEFAULT_VIEW_H_
 #define ASH_SYSTEM_TILES_TILES_DEFAULT_VIEW_H_
 
 #include "ash/ash_export.h"
-#include "ash/login_status.h"
 #include "base/macros.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/view.h"
 
 namespace views {
 class CustomButton;
 }
 
 namespace ash {
 class SystemTrayItem;
 
 // The container view for the tiles in the bottom row of the system menu
 // (settings, help, lock, and power).
 class ASH_EXPORT TilesDefaultView : public views::View,
                                     public views::ButtonListener {
  public:
-  TilesDefaultView(SystemTrayItem* owner, LoginStatus login);
+  explicit TilesDefaultView(SystemTrayItem* owner);
   ~TilesDefaultView() override;
 
   // Sets the layout manager and child views of |this|.
   // TODO(tdanderson|bruthig): Consider moving the layout manager
   // setup code to a location which can be shared by other system menu rows.
   void Init();
 
   // views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
   // Accessor needed to obtain the help button view for the first-run flow.
   views::View* GetHelpButtonView() const;
 
   const views::CustomButton* GetShutdownButtonViewForTest() const;
 
  private:
   friend class TrayTilesTest;
 
   SystemTrayItem* owner_;
-  LoginStatus login_;
 
   // Pointers to the child buttons of |this|. Note that some buttons may not
   // exist (depending on the user's current login status, for instance), in
   // which case the corresponding pointer will be null.
   views::CustomButton* settings_button_;
   views::CustomButton* help_button_;
   views::CustomButton* lock_button_;
   views::CustomButton* power_button_;
 
   DISALLOW_COPY_AND_ASSIGN(TilesDefaultView);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TILES_TILES_DEFAULT_VIEW_H_