[Sync] Moving DataTypeState to proto for serialization

sync/internal_api/public/simple_metadata_change_list.cc

 // 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.
 
 #include "sync/internal_api/public/simple_metadata_change_list.h"
 
 namespace syncer_v2 {
 
 SimpleMetadataChangeList::SimpleMetadataChangeList() {}
 
 SimpleMetadataChangeList::~SimpleMetadataChangeList() {}
 
 void SimpleMetadataChangeList::UpdateDataTypeState(
-    const DataTypeState& data_type_state) {
+    const sync_pb::DataTypeState& data_type_state) {
   // TODO(skym): Implementation.
 }
 
 void SimpleMetadataChangeList::UpdateMetadata(
     const std::string& client_tag,
     const sync_pb::EntityMetadata& metadata) {
   // TODO(skym): Implementation.
 }
 
 void SimpleMetadataChangeList::ClearDataTypeState() {
   // TODO(skym): Implementation.
 }
 
 void SimpleMetadataChangeList::ClearMetadata(const std::string& client_tag) {
   // TODO(skym): Implementation.
 }
 
 void SimpleMetadataChangeList::TranfserChanges(
     ModelTypeStore* store,
     ModelTypeStore::WriteBatch* write_batch) {
   // TODO(skym): Implementation.
 }
 
 }  // namespace syncer_v2