[Sync] Rename ModelEnumSet to ModelTypeSet

chrome/browser/sync/test/null_directory_change_delegate.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/sync/test/null_directory_change_delegate.h"
 
 namespace syncable {
 
 NullDirectoryChangeDelegate::~NullDirectoryChangeDelegate() {}
 
 void NullDirectoryChangeDelegate::HandleCalculateChangesChangeEventFromSyncApi(
     const ImmutableWriteTransactionInfo& write_transaction_info,
     BaseTransaction* trans) {}
 
 void NullDirectoryChangeDelegate::HandleCalculateChangesChangeEventFromSyncer(
     const ImmutableWriteTransactionInfo& write_transaction_info,
     BaseTransaction* trans) {}
 
-ModelEnumSet
+ModelTypeSet
     NullDirectoryChangeDelegate::HandleTransactionEndingChangeEvent(
         const ImmutableWriteTransactionInfo& write_transaction_info,
         BaseTransaction* trans) {
-  return ModelEnumSet();
+  return ModelTypeSet();
 }
 
 void NullDirectoryChangeDelegate::HandleTransactionCompleteChangeEvent(
-    ModelEnumSet models_with_changes) {}
+    ModelTypeSet models_with_changes) {}
 
 }  // namespace syncable