Removing PrefObserver usage, batch 4.

chrome/browser/media_gallery/media_file_system_registry.cc

 // 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.
 
 // MediaFileSystemRegistry implementation.
 
 #include "chrome/browser/media_gallery/media_file_system_registry.h"
 
 #include <set>
 #include <vector>
@@ skipping 472 matching lines @@
       preferences->GalleriesForExtension(*extension);
 
   if (galleries.empty()) {
     callback.Run(std::vector<MediaFileSystemInfo>());
     return;
   }
 
   if (!ContainsKey(pref_change_registrar_map_, profile)) {
     PrefChangeRegistrar* pref_registrar = new PrefChangeRegistrar;
     pref_registrar->Init(profile->GetPrefs());
-    pref_registrar->Add(prefs::kMediaGalleriesRememberedGalleries, this);
+    pref_registrar->Add(
+        prefs::kMediaGalleriesRememberedGalleries,
+        base::Bind(&MediaFileSystemRegistry::
+                   OnMediaGalleriesRememberedGalleriesChanged,
+                   base::Unretained(this),
+                   pref_registrar->prefs()));
     pref_change_registrar_map_[profile] = pref_registrar;
   }
 
   ExtensionGalleriesHost* extension_host =
       extension_hosts_map_[profile][extension->id()].get();
   if (!extension_host) {
     extension_host = new ExtensionGalleriesHost(
         file_system_context_.get(),
         base::Bind(&MediaFileSystemRegistry::OnExtensionGalleriesHostEmpty,
                    base::Unretained(this), profile, extension->id()));
@@ skipping 161 matching lines @@
     system_monitor->AddDevicesChangedObserver(this);
 }
 
 MediaFileSystemRegistry::~MediaFileSystemRegistry() {
   // SystemMonitor may be NULL in unit tests.
   SystemMonitor* system_monitor = SystemMonitor::Get();
   if (system_monitor)
     system_monitor->RemoveDevicesChangedObserver(this);
 }
 
-void MediaFileSystemRegistry::OnPreferenceChanged(
-    PrefServiceBase* prefs,
-    const std::string& pref_name) {
-  DCHECK_EQ(std::string(prefs::kMediaGalleriesRememberedGalleries), pref_name);
-
+void MediaFileSystemRegistry::OnMediaGalleriesRememberedGalleriesChanged(
+    PrefServiceBase* prefs) {
   // Find the Profile that contains the source PrefService.
   PrefChangeRegistrarMap::iterator pref_change_it =
       pref_change_registrar_map_.begin();
   for (; pref_change_it != pref_change_registrar_map_.end(); ++pref_change_it) {
     if (pref_change_it->first->GetPrefs() == prefs)
       break;
   }
   DCHECK(pref_change_it != pref_change_registrar_map_.end());
   Profile* profile = pref_change_it->first;
 
@@ skipping 61 matching lines @@
 
     PrefChangeRegistrarMap::iterator pref_it =
         pref_change_registrar_map_.find(profile);
     DCHECK(pref_it != pref_change_registrar_map_.end());
     delete pref_it->second;
     pref_change_registrar_map_.erase(pref_it);
   }
 }
 
 }  // namespace chrome