Introduce window container to be used by lock screen app windows

ash/tray_action/tray_action.h

 // Copyright 2017 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_TRAY_ACTION_TRAY_ACTION_H_
 #define ASH_TRAY_ACTION_TRAY_ACTION_H_
 
 #include "ash/ash_export.h"
 #include "ash/public/interfaces/tray_action.mojom.h"
 #include "base/macros.h"
@@ skipping 19 matching lines @@
   ~TrayAction() override;
 
   void AddObserver(TrayActionObserver* observer);
   void RemoveObserver(TrayActionObserver* observer);
 
   void BindRequest(mojom::TrayActionRequest request);
 
   // Gets last known handler state for the lock screen note action.
   // It will return kNotAvailable if an action handler has not been set using
   // |SetClient|.
-  mojom::TrayActionState GetLockScreenNoteState();
+  mojom::TrayActionState GetLockScreenNoteState() const;
+
+  // Helper method for determining if lock screen not action is in active state.
+  bool IsLockScreenNoteActive() const;
 
   // If the client is set, sends it a request to handle the lock screen note
   // action.
   void RequestNewLockScreenNote();
 
   // mojom::TrayAction:
   void SetClient(mojom::TrayActionClientPtr action_handler,
                  mojom::TrayActionState lock_screen_note_state) override;
   void UpdateLockScreenNoteState(mojom::TrayActionState state) override;
 
@@ skipping 11 matching lines @@
   mojo::BindingSet<mojom::TrayAction> bindings_;
 
   mojom::TrayActionClientPtr tray_action_client_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayAction);
 };
 
 }  // namespace ash
 
 #endif  // ASH_TRAY_ACTION_TRAY_ACTION_H_