Re-factor system tray code controlling launcher visibility

ash/system/status_area_widget.h

 // Copyright (c) 2012 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_STATUS_AREA_WIDGET_H_
 #define ASH_SYSTEM_STATUS_AREA_WIDGET_H_
 
 #include "ash/ash_export.h"
 #include "ash/launcher/background_animator.h"
 #include "ash/system/user/login_status.h"
@@ skipping 38 matching lines @@
   void SetHideSystemNotifications(bool hide);
 
   // Returns true if it is OK to show a non system notification.
   bool ShouldShowNonSystemNotifications();
 
   // Called by the client when the login status changes. Caches login_status
   // and calls UpdateAfterLoginStatusChange for the system tray and the web
   // notification tray.
   void UpdateAfterLoginStatusChange(user::LoginStatus login_status);
 
+  // Called whenever the launcher auto-hide behavior may need updating.
+  // This sets should_show_launcher_ and calls
+  // ShelfLayoutManager::UpdateAutoHideState() if the state has changed.
+  void UpdateShouldShowLauncher();
+
   internal::StatusAreaWidgetDelegate* status_area_widget_delegate() {
     return status_area_widget_delegate_;
   }
   SystemTray* system_tray() { return system_tray_; }
   SystemTrayDelegate* system_tray_delegate() {
     return system_tray_delegate_.get();
   }
   WebNotificationTray* web_notification_tray() {
     return web_notification_tray_;
   }
 
   user::LoginStatus login_status() const { return login_status_; }
 
+  bool should_show_launcher() const { return should_show_launcher_; }
+
  private:
   void AddSystemTray(ShellDelegate* shell_delegate);
   void AddWebNotificationTray();
 
   scoped_ptr<SystemTrayDelegate> system_tray_delegate_;
   // Weak pointers to View classes that are parented to StatusAreaWidget:
   internal::StatusAreaWidgetDelegate* status_area_widget_delegate_;
   SystemTray* system_tray_;
   WebNotificationTray* web_notification_tray_;
   user::LoginStatus login_status_;
+  bool should_show_launcher_;
 
   DISALLOW_COPY_AND_ASSIGN(StatusAreaWidget);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_STATUS_AREA_WIDGET_H_