Move common notification layout to base class

ash/system/network/tray_sms.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_NETWORK_TRAY_SMS_H
 #define ASH_SYSTEM_NETWORK_TRAY_SMS_H
 #pragma once
 
-#include "ash/system/tray/tray_image_item.h"
+#include <string>
+
+#include "ash/system/tray/system_tray_item.h"
 #include "base/memory/scoped_ptr.h"
 
 namespace ash {
 namespace internal {
 
-class TraySms : public TrayImageItem {
+class TraySms : public SystemTrayItem {
  public:
   TraySms();
   virtual ~TraySms();
 
   // Overridden from SystemTrayItem.
   virtual views::View* CreateDefaultView(user::LoginStatus status) OVERRIDE;
   virtual views::View* CreateDetailedView(user::LoginStatus status) OVERRIDE;
   virtual views::View* CreateNotificationView(
       user::LoginStatus status) OVERRIDE;
   virtual void DestroyDefaultView() OVERRIDE;
   virtual void DestroyDetailedView() OVERRIDE;
   virtual void DestroyNotificationView() OVERRIDE;
 
-  // Overridden from TrayImageItem.
-  virtual bool GetInitialVisibility() OVERRIDE;
-
  protected:
   class SmsDefaultView;
   class SmsDetailedView;
   class SmsMessageView;
   class SmsNotificationView;
   class SmsObserver;
 
+  // Gets the most recent message. Returns false if no messages or unable to
+  // retrieve the numebr and text from the message.
+  bool GetLatestMessage(size_t* index, std::string* number, std::string* text);
+
   // Called when sms messages have changed (by tray::SmsObserver).
   void Update(bool notify);
 
   SmsObserver* sms_observer() const { return sms_observer_.get(); }
 
  private:
   SmsDefaultView* default_;
   SmsDetailedView* detailed_;
   SmsNotificationView* notification_;
   scoped_ptr<SmsObserver> sms_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(TraySms);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_NETWORK_TRAY_SMS_H