[Sync] Move attachments code out of core/.

components/sync/engine/attachments/in_memory_attachment_store.cc

 // 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.
 
-#include "components/sync/core/attachments/in_memory_attachment_store.h"
+#include "components/sync/engine/attachments/in_memory_attachment_store.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/sequenced_task_runner.h"
 
 namespace syncer {
 
@@ skipping 140 matching lines @@
     : attachment(attachment) {
   components.insert(initial_reference_component);
 }
 
 InMemoryAttachmentStore::AttachmentEntry::AttachmentEntry(
     const AttachmentEntry& other) = default;
 
 InMemoryAttachmentStore::AttachmentEntry::~AttachmentEntry() {}
 
 }  // namespace syncer