Update sync API to support attachments.

sync/api/attachments/attachment_store.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_ATTACHMENT_STORE_H_
 #define SYNC_API_ATTACHMENTS_ATTACHMENT_STORE_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "sync/base/sync_export.h"
 
 namespace base {
 class RefCountedMemory;
 }  // namespace base
 
 namespace syncer {
 
 class Attachment;
 class AttachmentId;
 
 // A place to locally store and access Attachments.
 class SYNC_EXPORT AttachmentStore {
  public:
   AttachmentStore();
   virtual ~AttachmentStore();
 
   // TODO(maniscalco): Consider udpating Read and Write methods to support
-  // resumable transfers.
+  // resumable transfers (bug 353292).
 
   enum Result {
     SUCCESS,            // No error.
     NOT_FOUND,          // Attachment was not found or does not exist.
     UNSPECIFIED_ERROR,  // An unspecified error occurred.
   };
 
   typedef base::Callback<void(const Result&, scoped_ptr<Attachment>)>
       ReadCallback;
   typedef base::Callback<void(const Result&, const AttachmentId& id)>
@@ skipping 17 matching lines @@
   //
   // This does not remove the attachment from the server. |callback| will be
   // invoked when finished. If the attachment does not exist, |callback|'s
   // Result will be NOT_FOUND.
   virtual void Drop(const AttachmentId& id, const DropCallback& callback) = 0;
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_API_ATTACHMENTS_ATTACHMENT_STORE_H_