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

sync/syncable/in_memory_directory_backing_store.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 SYNC_SYNCABLE_IN_MEMORY_DIRECTORY_BACKING_STORE_H_
-#define SYNC_SYNCABLE_IN_MEMORY_DIRECTORY_BACKING_STORE_H_
-
-#include <string>
-
-#include "base/macros.h"
-#include "sync/base/sync_export.h"
-#include "sync/syncable/directory_backing_store.h"
-
-namespace syncer {
-namespace syncable {
-
-// This implementation of DirectoryBackingStore is used in tests that do not
-// require us to write to a file.  An in-memory sqlite database is much faster
-// than an on-disk database, so this can result in significant speedups in our
-// unit tests.
-//
-// An InMemoryDirectoryBackingStore cannot load data from existing databases.
-// When an InMemoryDirectoryBackingStore is destroyed, all data stored in this
-// database is lost.  If these limitations are a problem for you, consider using
-// TestDirectoryBackingStore.
-class SYNC_EXPORT InMemoryDirectoryBackingStore : public DirectoryBackingStore {
- public:
-  explicit InMemoryDirectoryBackingStore(const std::string& dir_name);
-  DirOpenResult Load(Directory::MetahandlesMap* handles_map,
-                     JournalIndex* delete_journals,
-                     MetahandleSet* metahandles_to_purge,
-                     Directory::KernelLoadInfo* kernel_load_info) override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(InMemoryDirectoryBackingStore);
-};
-
-}  // namespace syncable
-}  // namespace syncer
-
-#endif  // SYNC_SYNCABLE_IN_MEMORY_DIRECTORY_BACKING_STORE_H_