Remove NOTIFICATION_SYSTEM_SETTING_CHANGED, switch CrosSettings to base::CallbackRegistry.

chrome/browser/chromeos/login/wallpaper_manager.cc

 // Copyright (c) 2013 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 "chrome/browser/chromeos/login/wallpaper_manager.h"
 
 #include <vector>
 
 #include "ash/shell.h"
 #include "base/command_line.h"
@@ skipping 112 matching lines @@
 }
 
 // static
 WallpaperManager* WallpaperManager::Get() {
   if (!g_wallpaper_manager)
     g_wallpaper_manager = new WallpaperManager();
   return g_wallpaper_manager;
 }
 
 WallpaperManager::WallpaperManager()
-    : no_observers_(true),
-      loaded_wallpapers_(0),
+    : loaded_wallpapers_(0),
       wallpaper_loader_(new UserImageLoader(ImageDecoder::ROBUST_JPEG_CODEC)),
       command_line_for_testing_(NULL),
       should_cache_wallpaper_(false),
       weak_factory_(this) {
   registrar_.Add(this,
                  chrome::NOTIFICATION_LOGIN_USER_CHANGED,
                  content::NotificationService::AllSources());
   registrar_.Add(this,
                  chrome::NOTIFICATION_LOGIN_OR_LOCK_WEBUI_VISIBLE,
                  content::NotificationService::AllSources());
   registrar_.Add(this,
                  chrome::NOTIFICATION_WALLPAPER_ANIMATION_FINISHED,
                  content::NotificationService::AllSources());
   sequence_token_ = BrowserThread::GetBlockingPool()->
       GetNamedSequenceToken(kWallpaperSequenceTokenName);
   task_runner_ = BrowserThread::GetBlockingPool()->
       GetSequencedTaskRunnerWithShutdownBehavior(
           sequence_token_,
           base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
 }
 
 WallpaperManager::~WallpaperManager() {
   // TODO(bshe): Lifetime of WallpaperManager needs more consideration.
   // http://crbug.com/171694
-  DCHECK(no_observers_);
+  DCHECK(!show_user_name_on_signin_subscription_);
   ClearObsoleteWallpaperPrefs();
   weak_factory_.InvalidateWeakPtrs();
 }
 
 void WallpaperManager::Shutdown() {
-  CrosSettings::Get()->RemoveSettingsObserver(
-      kAccountsPrefShowUserNamesOnSignIn, this);
-  no_observers_ = true;
+  show_user_name_on_signin_subscription_.reset();
 }
 
 // static
 void WallpaperManager::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterDictionaryPref(prefs::kUsersWallpaperInfo);
   registry->RegisterDictionaryPref(kUserWallpapers);
   registry->RegisterDictionaryPref(kUserWallpapersProperties);
 }
 
 void WallpaperManager::AddObservers() {
-  CrosSettings::Get()->AddSettingsObserver(kAccountsPrefShowUserNamesOnSignIn,
-                                           this);
-  no_observers_ = false;
+  show_user_name_on_signin_subscription_ =
+      CrosSettings::Get()->AddSettingsObserver(
+          kAccountsPrefShowUserNamesOnSignIn,
+          base::Bind(&WallpaperManager::InitializeRegisteredDeviceWallpaper,
+                     base::Unretained(this)));
 }
 
 void WallpaperManager::EnsureLoggedInUserWallpaperLoaded() {
   // Some browser tests do not have a shell instance. As no wallpaper is needed
   // in these tests anyway, avoid loading one, preventing crashes and speeding
   // up the tests.
   if (!ash::Shell::HasInstance())
     return;
 
   WallpaperInfo info;
@@ skipping 112 matching lines @@
       if (should_cache_wallpaper_) {
         BrowserThread::PostDelayedTask(
             BrowserThread::UI, FROM_HERE,
             base::Bind(&WallpaperManager::CacheUsersWallpapers,
                        weak_factory_.GetWeakPtr()),
             base::TimeDelta::FromMilliseconds(kCacheWallpaperDelayMs));
         should_cache_wallpaper_ = false;
       }
       break;
     }
-    case chrome::NOTIFICATION_SYSTEM_SETTING_CHANGED: {
-      if (*content::Details<const std::string>(details).ptr() ==
-          kAccountsPrefShowUserNamesOnSignIn) {
-        InitializeRegisteredDeviceWallpaper();
-      }
-      break;
-    }
     default:
       NOTREACHED() << "Unexpected notification " << type;
   }
 }
 
 void WallpaperManager::RemoveUserWallpaperInfo(const std::string& email) {
   PrefService* prefs = g_browser_process->local_state();
   DictionaryPrefUpdate prefs_wallpapers_info_update(prefs,
       prefs::kUsersWallpaperInfo);
   prefs_wallpapers_info_update->RemoveWithoutPathExpansion(email, NULL);
@@ skipping 645 matching lines @@
   // |sequence_token_| here.
   wallpaper_loader_->Start(wallpaper_path.value(), 0, sequence_token_,
                            base::Bind(&WallpaperManager::OnWallpaperDecoded,
                                       base::Unretained(this),
                                       email,
                                       info.layout,
                                       update_wallpaper));
 }
 
 }  // namespace chromeos