Delete NativeMessageHandler once a native port closes.

runtime/vm/port.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/port.h"
 
 #include "vm/dart_entry.h"
 #include "platform/utils.h"
 #include "vm/dart_api_impl.h"
 #include "vm/isolate.h"
@@ skipping 198 matching lines @@
     if (map_[index].state == kLivePort) {
       handler->decrement_live_ports();
     }
 
     used_--;
     deleted_++;
     MaintainInvariants();
   }
   handler->ClosePort(port);
   if (!handler->HasLivePorts() && handler->OwnedByPortMap()) {
-    delete handler;
+    // Delete handler as soon as it isn't busy with a task.
+    handler->RequestDeletion();
   }
   return true;
 }
 
 
 void PortMap::ClosePorts(MessageHandler* handler) {
   {
     MutexLocker ml(mutex_);
     for (intptr_t i = 0; i < capacity_; i++) {
       if (map_[i].handler == handler) {
@@ skipping 108 matching lines @@
         OS::Print("Live Port = %" Pd64 "\n", map_[i].port);
         msg_handler = DartLibraryCalls::LookupHandler(map_[i].port);
         OS::Print("Handler = %s\n", msg_handler.ToCString());
       }
     }
   }
 }
 
 
 }  // namespace dart