Add TraySms for SMS messages.

ash/system/tray/system_tray_item.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_TRAY_SYSTEM_TRAY_ITEM_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_
 #pragma once
 
 #include "ash/ash_export.h"
 #include "ash/system/user/login_status.h"
@@ skipping 37 matching lines @@
   // These functions are called when the corresponding view item is about to be
   // removed. An item should do appropriate cleanup in these functions.
   // The default implementation does nothing.
   virtual void DestroyTrayView();
   virtual void DestroyDefaultView();
   virtual void DestroyDetailedView();
   virtual void DestroyNotificationView();
 
   // Updates the tray view (if applicable) when the user's login status changes.
   // It is not necessary the update the default or detailed view, since the
-  // default/detailed popup is closed when login status changes.
-  virtual void UpdateAfterLoginStatusChange(user::LoginStatus status) = 0;
+  // default/detailed popup is closed when login status changes. The default
+  // implementation does nothing.
+  virtual void UpdateAfterLoginStatusChange(user::LoginStatus status);
 
   // Pops up the detailed view for this item. An item can request to show its
   // detailed view using this function (e.g. from an observer callback when
   // something, e.g. volume, network availability etc. changes). If
   // |for_seconds| is non-zero, then the popup is closed after the specified
   // time.
   void PopupDetailedView(int for_seconds, bool activate);
 
   // Continue showing the currently-shown detailed view, if any, for
   // |for_seconds| seconds.  The caller is responsible for checking that the
   // currently-shown view is for this item.
   void SetDetailedViewCloseDelay(int for_seconds);
 
+  // Hides the detailed view for this item.
+  void HideDetailedView();
+
   // Shows a notification for this item.
   void ShowNotificationView();
 
   // Hides the notification for this item.
   void HideNotificationView();
 
  private:
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_ITEM_H_