Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/content_settings/cookie_settings.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/cookie_settings.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/content_settings/content_settings_utils.h"
 #include "chrome/browser/content_settings/host_content_settings_map.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ skipping 137 matching lines @@
 }
 
 void CookieSettings::ResetCookieSetting(
     const ContentSettingsPattern& primary_pattern,
     const ContentSettingsPattern& secondary_pattern) {
   host_content_settings_map_->SetContentSetting(
       primary_pattern, secondary_pattern, CONTENT_SETTINGS_TYPE_COOKIES, "",
       CONTENT_SETTING_DEFAULT);
 }
 
-void CookieSettings::Observe(int type,
-                             const content::NotificationSource& source,
-                             const content::NotificationDetails& details) {
+void CookieSettings::OnPreferenceChanged(PrefServiceBase* prefs,
+                                         const std::string& name) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DCHECK_EQ(chrome::NOTIFICATION_PREF_CHANGED, type);
-  DCHECK_EQ(std::string(prefs::kBlockThirdPartyCookies),
-            *content::Details<std::string>(details).ptr());
+  DCHECK_EQ(std::string(prefs::kBlockThirdPartyCookies), name);
 
-  PrefService* prefs = content::Source<PrefService>(source).ptr();
-  {
-    base::AutoLock auto_lock(lock_);
-    block_third_party_cookies_ = prefs->GetBoolean(
-        prefs::kBlockThirdPartyCookies);
-  }
+  base::AutoLock auto_lock(lock_);
+  block_third_party_cookies_ = prefs->GetBoolean(
+      prefs::kBlockThirdPartyCookies);
 }
 
 void CookieSettings::ShutdownOnUIThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   pref_change_registrar_.RemoveAll();
 }
 
 ContentSetting CookieSettings::GetCookieSetting(
     const GURL& url,
     const GURL& first_party_url,
@@ skipping 36 matching lines @@
   DCHECK(value.get());
   return content_settings::ValueToContentSetting(value.get());
 }
 
 CookieSettings::~CookieSettings() {}
 
 bool CookieSettings::ShouldBlockThirdPartyCookies() const {
   base::AutoLock auto_lock(lock_);
   return block_third_party_cookies_;
 }