Revert of Refactor FakeAttachmentStore

sync/internal_api/public/attachments/in_memory_attachment_store.h

-// Copyright 2014 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_ATTACHMENTS_IN_MEMORY_ATTACHMENT_STORE_H_
-#define SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_IN_MEMORY_ATTACHMENT_STORE_H_
-
-#include "base/memory/ref_counted.h"
-#include "base/single_thread_task_runner.h"
-#include "base/threading/non_thread_safe.h"
-#include "sync/api/attachments/attachment.h"
-#include "sync/api/attachments/attachment_id.h"
-#include "sync/api/attachments/attachment_store.h"
-#include "sync/base/sync_export.h"
-
-namespace syncer {
-
-// An in-memory implementation of AttachmentStore used for testing.
-// InMemoryAttachmentStore is not threadsafe, it lives on backend thread and
-// posts callbacks with results on |callback_task_runner|.
-class SYNC_EXPORT InMemoryAttachmentStore : public AttachmentStoreBase,
-                                            public base::NonThreadSafe {
- public:
-  InMemoryAttachmentStore(
-      const scoped_refptr<base::SingleThreadTaskRunner>& callback_task_runner);
-  virtual ~InMemoryAttachmentStore();
-
-  // AttachmentStoreBase implementation.
-  virtual void Read(const AttachmentIdList& ids,
-                    const ReadCallback& callback) OVERRIDE;
-  virtual void Write(const AttachmentList& attachments,
-                     const WriteCallback& callback) OVERRIDE;
-  virtual void Drop(const AttachmentIdList& ids,
-                    const DropCallback& callback) OVERRIDE;
-
- private:
-  scoped_refptr<base::SingleThreadTaskRunner> callback_task_runner_;
-  AttachmentMap attachments_;
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_IN_MEMORY_ATTACHMENT_STORE_H_