Auto create ApiLocalScope before calling native functions, this ensures that

runtime/bin/eventhandler.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 "bin/dartutils.h"
 #include "bin/eventhandler.h"
 #include "bin/socket.h"
 #include "bin/thread.h"
 
 #include "include/dart_api.h"
@@ skipping 71 matching lines @@
   event_handler = EventHandler::Start();
 }
 
 
 /*
  * Send data to the EventHandler thread to register for a given instance
  * args[1] a ReceivePort args[2] with a notification event args[3]. args[0]
  * holds the reference to the dart EventHandler object.
  */
 void FUNCTION_NAME(EventHandler_SendData)(Dart_NativeArguments args) {
-  Dart_EnterScope();
   Dart_Handle sender = Dart_GetNativeArgument(args, 1);
   intptr_t id = kInvalidId;
   if (Dart_IsNull(sender)) {
     id = kTimerId;
   } else {
     Socket::GetSocketIdNativeField(sender, &id);
   }
   Dart_Handle handle = Dart_GetNativeArgument(args, 2);
   Dart_Port dart_port =
       DartUtils::GetIntegerField(handle, DartUtils::kIdFieldName);
   int64_t data = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 3));
   {
     MutexLocker locker(mutex_);
     // Only send if the event_handler is not NULL. This means that the handler
     // shut down, and a message is send later on.
     if (event_handler != NULL) {
       event_handler->SendData(id, dart_port, data);
     }
   }
-  Dart_ExitScope();
 }
 
 }  // namespace bin
 }  // namespace dart