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

ash/system/web_notification/web_notification_tray.h

Index: ash/system/web_notification/web_notification_tray.h
diff --git a/ash/system/web_notification/web_notification_tray.h b/ash/system/web_notification/web_notification_tray.h
index 920baa4d2673727acffbe36d457aa133026eff01..9dd0109255287099280aeee69b63c207e28f15fe 100644
--- a/ash/system/web_notification/web_notification_tray.h
+++ b/ash/system/web_notification/web_notification_tray.h
@@ -134,7 +134,7 @@ class ASH_EXPORT WebNotificationTray
 
   // Queries login status and the status area widget to determine visibility of
   // the message center.
-  bool ShouldShowMessageCenter();
+  bool ShouldShowMessageCenter() const;
 
   // Returns true if it should show the quiet mode menu.
   bool ShouldShowQuietModeMenu(const ui::Event& event);
@@ -149,10 +149,6 @@ class ASH_EXPORT WebNotificationTray
     return message_center_bubble_.get();
   }
 
-  // Returns true if any user is logged in and the system is not at the screen
-  // for adding a secondary user.
-  bool IsLoggedIn() const;
-
   // Testing accessors.
   bool IsPopupVisible() const;
   message_center::MessageCenterBubble* GetMessageCenterBubbleForTest();