[mojo-edk] Fix race in port closure

mojo/edk/system/ports/node.cc

Index: mojo/edk/system/ports/node.cc
diff --git a/mojo/edk/system/ports/node.cc b/mojo/edk/system/ports/node.cc
index 1bee00caf1ff3bab8524d578fbe353bd89764316..5a5d83454197d0118c13a7d46ef138e709fde9fb 100644
--- a/mojo/edk/system/ports/node.cc
+++ b/mojo/edk/system/ports/node.cc
@@ -213,13 +213,13 @@ int Node::ClosePort(const PortRef& port_ref) {
     // If the port being closed still has unread messages, then we need to take
     // care to close those ports so as to avoid leaking memory.
     port->message_queue.GetReferencedPorts(&referenced_port_names);
+
+    ErasePort_Locked(port_ref.name());
   }
 
   DVLOG(2) << "Sending ObserveClosure from " << port_ref.name() << "@" << name_
            << " to " << peer_port_name << "@" << peer_node_name;
 
-  ErasePort(port_ref.name());
-
   delegate_->ForwardMessage(
       peer_node_name,
       NewInternalMessage(peer_port_name, EventType::kObserveClosure, data));