Get rid of the ability to unregister preferences.

chrome/browser/prefs/pref_model_associator.h

 // 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.
 
 #ifndef CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_
 #define CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 48 matching lines @@
   // Register a preference with the specified name for syncing. We do not care
   // about the type at registration time, but when changes arrive from the
   // syncer, we check if they can be applied and if not drop them.
   // Note: This should only be called at profile startup time (before sync
   // begins).
   virtual void RegisterPref(const char* name);
 
   // Returns true if the specified preference is registered for syncing.
   virtual bool IsPrefRegistered(const char* name);
 
-  // Unregisters a previously registered preference. This must be called
-  // prior to making the first sync.
-  virtual void UnregisterPref(const char* name);
-
   // Process a local preference change. This can trigger new SyncChanges being
   // sent to the syncer.
   virtual void ProcessPrefChange(const std::string& name);
 
   void SetPrefService(PrefServiceSyncable* pref_service);
 
   // Merges the local_value into the supplied server_value and returns
   // the result (caller takes ownership). If there is a conflict, the server
   // value always takes precedence. Note that only certain preferences will
   // actually be merged, all others will return a copy of the server value. See
@@ skipping 67 matching lines @@
   // Sync's syncer::SyncChange handler. We push all our changes through this.
   scoped_ptr<syncer::SyncChangeProcessor> sync_processor_;
 
   // Sync's error handler. We use this to create sync errors.
   scoped_ptr<syncer::SyncErrorFactory> sync_error_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefModelAssociator);
 };
 
 #endif  // CHROME_BROWSER_PREFS_PREF_MODEL_ASSOCIATOR_H_