[Sync] Move //sync to //components/sync.

sync/api/data_batch.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_API_DATA_BATCH_H_
-#define SYNC_API_DATA_BATCH_H_
-
-#include <algorithm>
-#include <memory>
-#include <string>
-#include <utility>
-
-#include "sync/api/entity_data.h"
-#include "sync/base/sync_export.h"
-
-namespace syncer_v2 {
-
-typedef std::pair<std::string, std::unique_ptr<EntityData>> TagAndData;
-
-// Interface used by the processor to read data requested from the service.
-class SYNC_EXPORT DataBatch {
- public:
-  DataBatch() {}
-  virtual ~DataBatch() {}
-
-  // Returns if the data batch has another pair or not.
-  virtual bool HasNext() const = 0;
-
-  // Returns a pair of storage tag and owned entity data object. Invoking this
-  // method will remove the pair from the batch, and should not be called if
-  // HasNext() returns false.
-  virtual TagAndData Next() = 0;
-};
-
-}  // namespace syncer_v2
-
-#endif  // SYNC_API_DATA_BATCH_H_