Draft change to use base::Closure instead of PrefObserver in PrefChangeRegistrar.

chrome/browser/prefs/pref_service.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/prefs/pref_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 751 matching lines @@
     return NULL;
   }
   const Value* value = pref->GetValue();
   if (value->GetType() != Value::TYPE_LIST) {
     NOTREACHED();
     return NULL;
   }
   return static_cast<const ListValue*>(value);
 }
 
-void PrefService::AddPrefObserver(const char* path, PrefObserver* obs) {
+void PrefService::AddPrefObserver(const char* path, const base::Closure& obs) {
   pref_notifier_->AddPrefObserver(path, obs);
 }
 
-void PrefService::RemovePrefObserver(const char* path, PrefObserver* obs) {
+void PrefService::RemovePrefObserver(const char* path,
+                                     const base::Closure& obs) {
   pref_notifier_->RemovePrefObserver(path, obs);
 }
 
 void PrefService::AddPrefInitObserver(base::Callback<void(bool)> obs) {
   pref_notifier_->AddInitObserver(obs);
 }
 
 void PrefService::RegisterPreference(const char* path,
                                      Value* default_value,
                                      PrefSyncStatus sync_status) {
@@ skipping 272 matching lines @@
   return pref_value_store()->PrefValueFromDefaultStore(name_.c_str());
 }
 
 bool PrefService::Preference::IsUserModifiable() const {
   return pref_value_store()->PrefValueUserModifiable(name_.c_str());
 }
 
 bool PrefService::Preference::IsExtensionModifiable() const {
   return pref_value_store()->PrefValueExtensionModifiable(name_.c_str());
 }