[Sync] Move attachments code out of core/.

components/sync/core/attachments/attachment_uploader.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 COMPONENTS_SYNC_CORE_ATTACHMENTS_ATTACHMENT_UPLOADER_H_
-#define COMPONENTS_SYNC_CORE_ATTACHMENTS_ATTACHMENT_UPLOADER_H_
-
-#include "base/callback.h"
-#include "components/sync/api/attachments/attachment.h"
-
-namespace syncer {
-
-// AttachmentUploader is responsible for uploading attachments to the server.
-class AttachmentUploader {
- public:
-  // The result of an UploadAttachment operation.
-  enum UploadResult {
-    UPLOAD_SUCCESS,            // No error, attachment was uploaded
-                               // successfully.
-    UPLOAD_TRANSIENT_ERROR,    // A transient error occurred, try again later.
-    UPLOAD_UNSPECIFIED_ERROR,  // An unspecified error occurred.
-  };
-
-  typedef base::Callback<void(const UploadResult&, const AttachmentId&)>
-      UploadCallback;
-
-  AttachmentUploader();
-  virtual ~AttachmentUploader();
-
-  // Upload |attachment| and invoke |callback| when done.
-  //
-  // |callback| will be invoked when the operation has completed (successfully
-  // or otherwise).
-  //
-  // |callback| will receive an UploadResult code and the AttachmentId of the
-  // newly uploaded attachment.
-  virtual void UploadAttachment(const Attachment& attachment,
-                                const UploadCallback& callback) = 0;
-};
-
-}  // namespace syncer
-
-#endif  // COMPONENTS_SYNC_CORE_ATTACHMENTS_ATTACHMENT_UPLOADER_H_