Open apps section on NTP when new app get installed

chrome/browser/dom_ui/shown_sections_handler.h

 // Copyright (c) 2010 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 CHROME_BROWSER_DOM_UI_SHOWN_SECTIONS_HANDLER_H_
 #define CHROME_BROWSER_DOM_UI_SHOWN_SECTIONS_HANDLER_H_
 #pragma once
 
 #include "chrome/browser/dom_ui/dom_ui.h"
 #include "chrome/common/notification_observer.h"
-#include "chrome/common/notification_registrar.h"
 #include "chrome/browser/prefs/pref_change_registrar.h"
 
 class DOMUI;
+class Extension;
 class Value;
 class PrefService;
 
 // Use for the shown sections bitmask.
 // Currently, only the THUMB and APPS sections can be toggled by the user. Other
 // sections are shown automatically if they have data, and hidden otherwise.
 enum Section {
   // If one of these is set, the corresponding section shows large thumbnails,
   // else it shows only a small overview list.
   THUMB = 1 << 0,
@@ skipping 31 matching lines @@
 
   // Callback for "setShownSections" message.
   void HandleSetShownSections(const ListValue* args);
 
   static void RegisterUserPrefs(PrefService* pref_service);
 
   static void MigrateUserPrefs(PrefService* pref_service,
                                int old_pref_version,
                                int new_pref_version);
 
+  static void OnExtensionInstalled(PrefService* prefs,
+                                   const Extension* extension);
+
  private:
   PrefService* pref_service_;
   PrefChangeRegistrar pref_registrar_;
-  NotificationRegistrar notification_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ShownSectionsHandler);
 };
 
 #endif  // CHROME_BROWSER_DOM_UI_SHOWN_SECTIONS_HANDLER_H_