[Sync] Move some directory-related things from core/ to syncable/.

components/sync/core/read_transaction.h

-// Copyright 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_CORE_READ_TRANSACTION_H_
-#define COMPONENTS_SYNC_CORE_READ_TRANSACTION_H_
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include <string>
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "components/sync/core/base_transaction.h"
-#include "components/sync/model/attachments/attachment_id.h"
-
-namespace tracked_objects {
-class Location;
-}  // namespace tracked_objects
-
-namespace sync_pb {
-class DataTypeContext;
-}
-
-namespace syncer {
-
-struct UserShare;
-
-// Sync API's ReadTransaction is a read-only BaseTransaction.  It wraps
-// a syncable::ReadTransaction.
-class ReadTransaction : public BaseTransaction {
- public:
-  // Start a new read-only transaction on the specified repository.
-  ReadTransaction(const tracked_objects::Location& from_here, UserShare* share);
-
-  // Resume the middle of a transaction. Will not close transaction.
-  ReadTransaction(UserShare* share, syncable::BaseTransaction* trans);
-
-  ~ReadTransaction() override;
-
-  // BaseTransaction override.
-  syncable::BaseTransaction* GetWrappedTrans() const override;
-
-  // Return |transaction_version| of |type| stored in sync directory's
-  // persisted info.
-  int64_t GetModelVersion(ModelType type) const;
-
-  // Fills |context| with the datatype context associated with |type|.
-  void GetDataTypeContext(ModelType type,
-                          sync_pb::DataTypeContext* context) const;
-
-  // Clear |ids| and fill it with the ids of attachments that need to be
-  // uploaded to the sync server.
-  void GetAttachmentIdsToUpload(ModelType type, AttachmentIdList* ids) const;
-
-  // Return the current (opaque) store birthday.
-  std::string GetStoreBirthday() const;
-
- private:
-  void* operator new(size_t size);  // Transaction is meant for stack use only.
-
-  // The underlying syncable object which this class wraps.
-  syncable::BaseTransaction* transaction_;
-  bool close_transaction_;
-
-  DISALLOW_COPY_AND_ASSIGN(ReadTransaction);
-};
-
-}  // namespace syncer
-
-#endif  // COMPONENTS_SYNC_CORE_READ_TRANSACTION_H_