Use PrefChangeRegistrar everywhere

chrome/browser/background_mode_manager.cc

 // 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.
 
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "base/base_paths.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/logging.h"
@@ skipping 145 matching lines @@
   // while Chrome was not running.
   registrar_.Add(this, NotificationType::EXTENSIONS_READY,
                  Source<Profile>(profile));
 
   // Listen for the application shutting down so we can decrement our KeepAlive
   // count.
   registrar_.Add(this, NotificationType::APP_TERMINATING,
                  NotificationService::AllSources());
 
   // Listen for changes to the background mode preference.
-  profile_->GetPrefs()->AddPrefObserver(prefs::kBackgroundModeEnabled, this);
+  pref_registrar_.Init(profile_->GetPrefs());
+  pref_registrar_.Add(prefs::kBackgroundModeEnabled, this);
 }
 
 BackgroundModeManager::~BackgroundModeManager() {
   // We're going away, so exit background mode (does nothing if we aren't in
   // background mode currently). This is primarily needed for unit tests,
   // because in an actual running system we'd get an APP_TERMINATING
   // notification before being destroyed.
   EndBackgroundMode();
-  // Manually remove our pref observer so we don't get notified for prefs
-  // changes (have to do it manually because we can't use the registrar for
-  // prefs notifications).
-  profile_->GetPrefs()->RemovePrefObserver(prefs::kBackgroundModeEnabled, this);
 }
 
 bool BackgroundModeManager::IsBackgroundModeEnabled() {
   return profile_->GetPrefs()->GetBoolean(prefs::kBackgroundModeEnabled);
 }
 
 bool BackgroundModeManager::IsLaunchOnStartupResetAllowed() {
   return profile_->GetPrefs()->GetBoolean(prefs::kLaunchOnStartupResetAllowed);
 }
 
@@ skipping 279 matching lines @@
     browser = BrowserList::GetLastActive();
   }
   return browser;
 }
 
 // static
 void BackgroundModeManager::RegisterUserPrefs(PrefService* prefs) {
   prefs->RegisterBooleanPref(prefs::kBackgroundModeEnabled, true);
   prefs->RegisterBooleanPref(prefs::kLaunchOnStartupResetAllowed, false);
 }