Make sure the app section opens whenever a new apps is

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 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,
   APPS = 1 << 6,
 
+  // We use the low 16 bits for sections, the high 16 bits for minimized state.
+  ALL_SECTIONS_MASK = 0x0000FFFF,
+
   // If one of these is set, then the corresponding section is shown minimized
   // at the bottom of the NTP and no data is directly visible on the NTP.
   MINIMIZED_THUMB = 1 << (0 + 16),
   MINIMIZED_RECENT = 1 << (2 + 16),
   MINIMIZED_APPS = 1 << (6 + 16),
 };
 
 class ShownSectionsHandler : public DOMMessageHandler,
                              public NotificationObserver {
  public:
@@ skipping 18 matching lines @@
   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);
 
  private:
   PrefService* pref_service_;
-  PrefChangeRegistrar registrar_;
+  PrefChangeRegistrar pref_registrar_;
+  NotificationRegistrar notification_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ShownSectionsHandler);
 };
 
 #endif  // CHROME_BROWSER_DOM_UI_SHOWN_SECTIONS_HANDLER_H_