Add TraySms for SMS messages.

ash/system/tray/system_tray.h

Index: ash/system/tray/system_tray.h
diff --git a/ash/system/tray/system_tray.h b/ash/system/tray/system_tray.h
index 376fea4fa1114b45cbde16dec4e91b58e143c26f..cf1781da5ca0c074e198c26a7da3c3a8e760c04a 100644
--- a/ash/system/tray/system_tray.h
+++ b/ash/system/tray/system_tray.h
@@ -72,6 +72,9 @@ class ASH_EXPORT SystemTray : public internal::ActionableView,
   // seconds.
   void SetDetailedViewCloseDelay(int close_delay);
 
+  // Hides the detailed view for |item|.
+  void HideDetailedView(SystemTrayItem* item);
+
   // Shows the notification view for |item|.
   void ShowNotificationView(SystemTrayItem* item);
 
@@ -172,8 +175,11 @@ class ASH_EXPORT SystemTray : public internal::ActionableView,
   // Overridden from internal::BackgroundAnimatorDelegate.
   virtual void UpdateBackground(int alpha) OVERRIDE;
 
+  // Owned items.
   ScopedVector<SystemTrayItem> items_;
 
+  // Pointers to members of |items_|.
+  SystemTrayItem* detailed_item_;
   std::vector<SystemTrayItem*> notification_items_;
 
   // The container for all the tray views of the items.