Update sync API to support attachments.

sync/internal_api/base_node.cc

Index: sync/internal_api/base_node.cc
diff --git a/sync/internal_api/base_node.cc b/sync/internal_api/base_node.cc
index ac047686a5f1c0b9d83555230c3c12453a548f62..078839540e3e66c4a9bfeb5ccd32646fa86410b6 100644
--- a/sync/internal_api/base_node.cc
+++ b/sync/internal_api/base_node.cc
@@ -290,6 +290,13 @@ ModelType BaseNode::GetModelType() const {
   return GetEntry()->GetModelType();
 }
 
+const syncer::AttachmentIdList BaseNode::GetAttachmentIds() const {
+  // TODO(maniscalco): Once EntryKernel is capable of storing AttachmentIds,
+  // update this method to retrieve the list of AttachmentIds from read_node and
+  // pass it to CreateRemoteData (bug 348625).
+  return AttachmentIdList();
+}
+
 void BaseNode::SetUnencryptedSpecifics(
     const sync_pb::EntitySpecifics& specifics) {
   ModelType type = GetModelTypeFromSpecifics(specifics);