[Sync] Move attachments code out of core/.

components/sync/engine/attachments/attachment_store_backend.h

Index: components/sync/engine/attachments/attachment_store_backend.h
diff --git a/components/sync/api/attachments/attachment_store_backend.h b/components/sync/engine/attachments/attachment_store_backend.h
similarity index 92%
rename from components/sync/api/attachments/attachment_store_backend.h
rename to components/sync/engine/attachments/attachment_store_backend.h
index a014d68f9eab6ebc32facb8d417d870a658284a6..85f5af9b202203a627346ef73fc2916863bf2ecc 100644
--- a/components/sync/api/attachments/attachment_store_backend.h
+++ b/components/sync/engine/attachments/attachment_store_backend.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_API_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_
-#define COMPONENTS_SYNC_API_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_
+#ifndef COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_
+#define COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_
 
 #include "base/callback.h"
 #include "base/macros.h"
@@ -65,4 +65,4 @@ class AttachmentStoreBackend {
 
 }  // namespace syncer
 
-#endif  // COMPONENTS_SYNC_API_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_
+#endif  // COMPONENTS_SYNC_ENGINE_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_