Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/content_settings/content_settings_pref_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_pref_provider.h"
 
 #include <map>
 #include <string>
 #include <utility>
 
@@ skipping 199 matching lines @@
         content_type,
         "",
         NULL);
   }
   NotifyObservers(ContentSettingsPattern(),
                   ContentSettingsPattern(),
                   content_type,
                   std::string());
 }
 
-void PrefProvider::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
+void PrefProvider::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(std::string(prefs::kContentSettingsPatternPairs),
-            *content::Details<std::string>(details).ptr());
+  DCHECK_EQ(prefs_, service);
+  DCHECK_EQ(std::string(prefs::kContentSettingsPatternPairs), name);
 
   if (updating_preferences_)
     return;
 
   ReadContentSettingsFromPref(true);
 
   NotifyObservers(ContentSettingsPattern(),
                   ContentSettingsPattern(),
                   CONTENT_SETTINGS_TYPE_DEFAULT,
                   std::string());
@@ skipping 455 matching lines @@
 
 void PrefProvider::AssertLockNotHeld() const {
 #if !defined(NDEBUG)
   // |Lock::Acquire()| will assert if the lock is held by this thread.
   lock_.Acquire();
   lock_.Release();
 #endif
 }
 
 }  // namespace content_settings