[Sync] Moving DataTypeState to proto for serialization

sync/internal_api/public/simple_metadata_change_list.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 SYNC_INTERNAL_API_PUBLIC_SIMPLE_METADATA_CHANGE_LIST_H_
 #define SYNC_INTERNAL_API_PUBLIC_SIMPLE_METADATA_CHANGE_LIST_H_
 
+#include <string>
+
 #include "sync/api/metadata_change_list.h"
 #include "sync/api/model_type_store.h"
 #include "sync/base/sync_export.h"
 
 namespace syncer_v2 {
 
 // A MetadataChangeList implementation that is meant to be used in combination
 // with a ModelTypeStore. It accumulates changes in member fields, and then when
 // requested transfers them to the store/write batch.
 class SYNC_EXPORT SimpleMetadataChangeList : public MetadataChangeList {
  public:
   SimpleMetadataChangeList();
   ~SimpleMetadataChangeList() override;
 
-  void UpdateDataTypeState(const DataTypeState& data_type_state) override;
+  void UpdateDataTypeState(
+      const sync_pb::DataTypeState& data_type_state) override;
   void ClearDataTypeState() override;
   void UpdateMetadata(const std::string& client_tag,
                       const sync_pb::EntityMetadata& metadata) override;
   void ClearMetadata(const std::string& client_tag) override;
 
   // Moves all currently accumulated changes into the write batch, clear out
   // local copies. Calling this multiple times will work, but should not be
   // necessary.
   void TranfserChanges(ModelTypeStore* store,
                        ModelTypeStore::WriteBatch* write_batch);
 };
 
 }  // namespace syncer_v2
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_SIMPLE_METADATA_CHANGE_LIST_H_