cros: Use SessionController to enable system tray settings / notifications tray

ash/session/session_controller.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_SESSION_SESSION_CONTROLLER_H_
 #define ASH_SESSION_SESSION_CONTROLLER_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 51 matching lines @@
   bool ShouldLockScreenAutomatically() const;
 
   // Returns true if user session blocked by some overlying UI. It can be
   // login screen, lock screen or screen for adding users into multi-profile
   // session.
   bool IsUserSessionBlocked() const;
 
   // Convenience function that returns true if session state is LOGIN_SECONDARY.
   bool IsInSecondaryLoginScreen() const;
 
+  // Returns true if the settings icon should be enabled in the system tray.
+  bool ShouldEnableSettings() const;
+
+  // Returns true if the notification tray should appear.
+  bool ShouldShowNotificationTray() const;
+
   // Gets the ash session state.
   session_manager::SessionState GetSessionState() const;
 
   // Gets the user sessions in LRU order with the active session being first.
   const std::vector<mojom::UserSessionPtr>& GetUserSessions() const;
 
   // Convenience helper to gets the user session at a given index. Returns
   // nullptr if no user session is found for the index.
   const mojom::UserSession* GetUserSession(UserIndex index) const;
 
@@ skipping 72 matching lines @@
   bool is_unlocking_ = false;
 
   base::ObserverList<ash::SessionStateObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SESSION_SESSION_CONTROLLER_H_