[Sync] Move attachments code out of core/.

components/sync/engine/attachments/attachment_downloader.h

Index: components/sync/engine/attachments/attachment_downloader.h
diff --git a/components/sync/core/attachments/attachment_downloader.h b/components/sync/engine/attachments/attachment_downloader.h
similarity index 90%
rename from components/sync/core/attachments/attachment_downloader.h
rename to components/sync/engine/attachments/attachment_downloader.h
index 35c67b42fa821650f828550de3c5d85c07d0c574..840572731e400ae61b54543cf59c6671c76e9df3 100644
--- a/components/sync/core/attachments/attachment_downloader.h
+++ b/components/sync/engine/attachments/attachment_downloader.h
@@ -2,8 +2,8 @@
 // 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_DOWNLOADER_H_
-#define COMPONENTS_SYNC_CORE_ATTACHMENTS_ATTACHMENT_DOWNLOADER_H_
+#ifndef COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_DOWNLOADER_H_
+#define COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_DOWNLOADER_H_
 
 #include <memory>
 #include <string>
@@ -44,7 +44,8 @@ class AttachmentDownloader {
   virtual void DownloadAttachment(const AttachmentId& attachment_id,
                                   const DownloadCallback& callback) = 0;
 
-  // Create instance of AttachmentDownloaderImpl.
+  // Create an instance of AttachmentDownloader.
+  //
   // |sync_service_url| is the URL of the sync service.
   //
   // |url_request_context_getter| provides a URLRequestContext.
@@ -72,4 +73,4 @@ class AttachmentDownloader {
 
 }  // namespace syncer
 
-#endif  // COMPONENTS_SYNC_CORE_ATTACHMENTS_ATTACHMENT_DOWNLOADER_H_
+#endif  // COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_DOWNLOADER_H_