- Make sure to keep the main/control port opened until the

runtime/vm/message_handler.cc

Index: runtime/vm/message_handler.cc
===================================================================
--- runtime/vm/message_handler.cc	(revision 29277)
+++ runtime/vm/message_handler.cc	(working copy)
@@ -32,6 +32,7 @@
 MessageHandler::MessageHandler()
     : queue_(new MessageQueue()),
       oob_queue_(new MessageQueue()),
+      control_ports_(0),
       live_ports_(0),
       pool_(NULL),
       task_(NULL),
@@ -269,4 +270,22 @@
   live_ports_--;
 }
 
+
+void MessageHandler::increment_control_ports() {
+  MonitorLocker ml(&monitor_);
+#if defined(DEBUG)
+  CheckAccess();
+#endif
+  control_ports_++;
+}
+
+
+void MessageHandler::decrement_control_ports() {
+  MonitorLocker ml(&monitor_);
+#if defined(DEBUG)
+  CheckAccess();
+#endif
+  control_ports_--;
+}
+
 }  // namespace dart