Make LogoutButtonTray a regular View

ash/system/date/tray_system_info.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_DATE_TRAY_SYSTEM_INFO_H_
 #define ASH_SYSTEM_DATE_TRAY_SYSTEM_INFO_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 24 matching lines @@
   const tray::TimeView* GetTimeTrayForTesting() const;
   const SystemInfoDefaultView* GetDefaultViewForTesting() const;
   views::View* CreateDefaultViewForTesting(LoginStatus status);
 
  private:
   // SystemTrayItem:
   views::View* CreateTrayView(LoginStatus status) override;
   views::View* CreateDefaultView(LoginStatus status) override;
   void DestroyTrayView() override;
   void DestroyDefaultView() override;
-  void UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) override;
+  void UpdateAfterShelfAlignmentChange() override;
 
   // ClockObserver:
   void OnDateFormatChanged() override;
   void OnSystemClockTimeUpdated() override;
   void OnSystemClockCanSetTimeChanged(bool can_set_time) override;
   void Refresh() override;
 
   void SetupLabelForTimeTray(views::Label* label);
   void UpdateTimeFormat();
 
   tray::TimeView* tray_view_;
   SystemInfoDefaultView* default_view_;
   LoginStatus login_status_;
 
   std::unique_ptr<SystemClockObserver> system_clock_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(TraySystemInfo);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_DATE_TRAY_SYSTEM_INFO_H_