Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/content_settings/content_settings_default_provider.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.
 
 #include "chrome/browser/content_settings/content_settings_default_provider.h"
 
 #include <string>
 #include <vector>
 
 #include "base/auto_reset.h"
@@ skipping 258 matching lines @@
 }
 
 void DefaultProvider::ShutdownOnUIThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(prefs_);
   RemoveAllObservers();
   pref_change_registrar_.RemoveAll();
   prefs_ = NULL;
 }
 
-void DefaultProvider::Observe(int type,
-                              const content::NotificationSource& source,
-                              const content::NotificationDetails& details) {
+void DefaultProvider::OnPreferenceChanged(PrefServiceBase* service,
+                                          const std::string& name) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DCHECK_EQ(chrome::NOTIFICATION_PREF_CHANGED, type);
-  DCHECK_EQ(content::Source<PrefService>(source).ptr(), prefs_);
-
+  DCHECK_EQ(prefs_, service);
   if (updating_preferences_)
     return;
 
-  const std::string& name = *content::Details<std::string>(details).ptr();
   if (name == prefs::kDefaultContentSettings) {
     ReadDefaultSettings(true);
   } else if (name == prefs::kGeolocationDefaultContentSetting) {
     MigrateObsoleteGeolocationPref();
     // Return and don't send a notifications. Migrating the obsolete
     // geolocation pref will change the prefs::kDefaultContentSettings and
     // cause the notification to be fired.
     return;
   } else {
     NOTREACHED() << "Unexpected preference observed";
@@ skipping 83 matching lines @@
     SetWebsiteSetting(
         ContentSettingsPattern::Wildcard(),
         ContentSettingsPattern::Wildcard(),
         CONTENT_SETTINGS_TYPE_GEOLOCATION,
         std::string(),
         value->DeepCopy());
   }
 }
 
 }  // namespace content_settings