sync: Finish non-blocking type encryption support

sync/engine/model_type_sync_proxy_impl.cc

Index: sync/engine/model_type_sync_proxy_impl.cc
diff --git a/sync/engine/model_type_sync_proxy_impl.cc b/sync/engine/model_type_sync_proxy_impl.cc
index 7ea5d526214411fa504fb60767b137c325ee1553..d3e1d777901e87d57178b7379ebd323f5899c35c 100644
--- a/sync/engine/model_type_sync_proxy_impl.cc
+++ b/sync/engine/model_type_sync_proxy_impl.cc
@@ -240,6 +240,9 @@ void ModelTypeSyncProxyImpl::OnUpdateReceived(
     // commit to fix it.
     if (data_type_state_.encryption_key_name !=
         response_data.encryption_key_name) {
+      DVLOG(2) << ModelTypeToString(type_) << ": Requesting re-encrypt commit "
+               << response_data.encryption_key_name << " -> "
+               << data_type_state_.encryption_key_name;
       EntityMap::iterator it2 = entities_.find(client_tag_hash);
       it2->second->UpdateDesiredEncryptionKey(
           data_type_state_.encryption_key_name);