Remove some dead code about "acknowledged types"

components/sync_driver/sync_prefs.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 COMPONENTS_SYNC_DRIVER_SYNC_PREFS_H_
 #define COMPONENTS_SYNC_DRIVER_SYNC_PREFS_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 105 matching lines @@
   // Maps |data_type| to its corresponding preference name.
   static const char* GetPrefNameForDataType(syncer::ModelType data_type);
 
 #if defined(OS_CHROMEOS)
   // Use this spare bootstrap token only when setting up sync for the first
   // time.
   std::string GetSpareBootstrapToken() const;
   void SetSpareBootstrapToken(const std::string& token);
 #endif
 
-  // Merges the given set of types with the set of acknowledged types.
-  void AcknowledgeSyncedTypes(syncer::ModelTypeSet types);
-
   // Get/Set number of rollback attempts allowed.
   virtual int GetRemainingRollbackTries() const;
   virtual void SetRemainingRollbackTries(int times);
 
   // Get/set/clear first sync time of current user. Used to roll back browsing
   // data later when user signs out.
   base::Time GetFirstSyncTime() const;
   void SetFirstSyncTime(base::Time time);
   void ClearFirstSyncTime();
 
   // For testing.
 
   void SetManagedForTest(bool is_managed);
-  syncer::ModelTypeSet GetAcknowledgeSyncedTypesForTest() const;
 
  private:
   void RegisterPrefGroups();
 
   static void RegisterDataTypePreferredPref(
       user_prefs::PrefRegistrySyncable* prefs,
       syncer::ModelType type,
       bool is_preferred);
   bool GetDataTypePreferred(syncer::ModelType type) const;
   void SetDataTypePreferred(syncer::ModelType type, bool is_preferred);
@@ skipping 23 matching lines @@
   // etc.
   typedef std::map<syncer::ModelType, syncer::ModelTypeSet> PrefGroupsMap;
   PrefGroupsMap pref_groups_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncPrefs);
 };
 
 }  // namespace sync_driver
 
 #endif  // COMPONENTS_SYNC_DRIVER_SYNC_PREFS_H_