AttachmentDownloader implementation.

sync/internal_api/public/attachments/attachment_downloader_impl.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_ATTACHMENT_DOWNLOADER_IMPL_H_
+#define SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_DOWNLOADER_IMPL_H_
+
+#include "base/threading/non_thread_safe.h"
+#include "sync/api/attachments/attachment_downloader.h"
+
+namespace syncer {
+
+// An implementation of AttachmentDownloader.
+class SYNC_EXPORT AttachmentDownloaderImpl : public AttachmentDownloader,
+                                             public base::NonThreadSafe {
+ public:
+  AttachmentDownloaderImpl();
+  virtual ~AttachmentDownloaderImpl();
+
+  // AttachmentDownloader implementation.
+  virtual void DownloadAttachment(const AttachmentId& attachment_id,
+                                  const DownloadCallback& callback) OVERRIDE;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AttachmentDownloaderImpl);
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_DOWNLOADER_IMPL_H_