Remove year+ old migration support of "session.urls_to_restore_on_startup".

components/syncable_prefs/pref_model_associator_client.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 COMPONENTS_SYNCABLE_PREFS_PREF_MODEL_ASSOCIATOR_CLIENT_H_
 #define COMPONENTS_SYNCABLE_PREFS_PREF_MODEL_ASSOCIATOR_CLIENT_H_
 
 #include <string>
 
 #include "base/macros.h"
 
 namespace syncable_prefs {
 
 // This class allows the embedder to configure the PrefModelAssociator to
 // have a different behaviour when receiving preference synchronisations
 // events from the server.
 class PrefModelAssociatorClient {
  public:
   // Returns true if the preference named |pref_name| is a list preference
   // whose server value is merged with local value during synchronisation.
   virtual bool IsMergeableListPreference(
       const std::string& pref_name) const = 0;
 
   // Returns true if the preference named |pref_name| is a dictionary preference
   // whose server value is merged with local value during synchronisation.
   virtual bool IsMergeableDictionaryPreference(
       const std::string& pref_name) const = 0;
 
-  // Returns true if the preference named |new_pref_name| is the new name for
-  // an old preference. The old name will be returned via |old_pref_name|.
-  virtual bool IsMigratedPreference(const std::string& new_pref_name,
-                                    std::string* old_pref_name) const = 0;
-
-  // Returns true if the preference named |old_pref_name| is the new name for
-  // a new preference. The old name will be returned via |new_pref_name|.
-  virtual bool IsOldMigratedPreference(const std::string& old_pref_name,
-                                       std::string* new_pref_name) const = 0;
-
  protected:
   PrefModelAssociatorClient() {}
   virtual ~PrefModelAssociatorClient() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PrefModelAssociatorClient);
 };
 
 }  // namespace syncable_prefs
 
 #endif  // COMPONENTS_SYNCABLE_PREFS_PREF_MODEL_ASSOCIATOR_CLIENT_H_