WIP: Pref service: use the incognito support from Chrome

chrome/browser/prefs/pref_service_syncable_util.h

 // Copyright 2015 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.
 
 #ifndef CHROME_BROWSER_PREFS_PREF_SERVICE_SYNCABLE_UTIL_H_
 #define CHROME_BROWSER_PREFS_PREF_SERVICE_SYNCABLE_UTIL_H_
 
-class PrefStore;
 class Profile;
 
 namespace sync_preferences {
 class PrefServiceSyncable;
 }
 
 // sync_preferences::PrefServiceSyncable is a PrefService with added integration
 // for sync, and knowledge of how to create an incognito PrefService. For code
 // that does not need to know about the sync integration, you should use only
 // the plain PrefService type.
 //
 // For this reason, Profile does not expose an accessor for the
 // sync_preferences::PrefServiceSyncable type. Instead, you can use the
 // utilities below to retrieve the sync_preferences::PrefServiceSyncable (or its
 // incognito version) from a Profile.
 sync_preferences::PrefServiceSyncable* PrefServiceSyncableFromProfile(
     Profile* profile);
-sync_preferences::PrefServiceSyncable* PrefServiceSyncableIncognitoFromProfile(
-    Profile* profile);
-
-// Creates an incognito copy of |pref_service| that shares most prefs but uses
-// a fresh non-persistent overlay for the user pref store and an individual
-// extension pref store (to cache the effective extension prefs for incognito
-// windows).
-sync_preferences::PrefServiceSyncable* CreateIncognitoPrefServiceSyncable(
-    sync_preferences::PrefServiceSyncable* pref_service,
-    PrefStore* incognito_extension_pref_store);
 
 #endif  // CHROME_BROWSER_PREFS_PREF_SERVICE_SYNCABLE_UTIL_H_