Refactor preference syncing.

chrome/browser/net/pref_proxy_config_service.cc

 // Copyright (c) 2011 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/net/pref_proxy_config_service.h"
 
 #include "base/values.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/pref_set_observer.h"
 #include "chrome/browser/prefs/proxy_config_dictionary.h"
@@ skipping 251 matching lines @@
   if (!registered_observers_) {
     base_service_->AddObserver(this);
     pref_config_tracker_->AddObserver(this);
     registered_observers_ = true;
   }
 }
 
 // static
 void PrefProxyConfigService::RegisterPrefs(PrefService* pref_service) {
   DictionaryValue* default_settings = ProxyConfigDictionary::CreateSystem();
-  pref_service->RegisterDictionaryPref(prefs::kProxy, default_settings);
+  pref_service->RegisterDictionaryPref(prefs::kProxy,
+                                       default_settings,
+                                       PrefService::UNSYNCABLE_PREF);
 }