Add AttachmentUploader interface and fake implementation.

sync/api/attachments/fake_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 SYNC_API_ATTACHMENTS_FAKE_ATTACHMENT_UPLOADER_H_
+#define SYNC_API_ATTACHMENTS_FAKE_ATTACHMENT_UPLOADER_H_
+
+#include "base/threading/non_thread_safe.h"
+#include "sync/api/attachments/attachment_uploader.h"
+
+namespace syncer {
+
+// A fake implementation of AttachmentUploader.
+class SYNC_EXPORT FakeAttachmentUploader : public AttachmentUploader,
+                                           public base::NonThreadSafe {
+ public:
+  FakeAttachmentUploader();
+  virtual ~FakeAttachmentUploader();
+
+  // AttachmentUploader implementation.
+  virtual void UploadAttachment(const Attachment& attachment,
+                                const UploadCallback& callback) OVERRIDE;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FakeAttachmentUploader);
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_API_ATTACHMENTS_FAKE_ATTACHMENT_UPLOADER_H_