Fix for issue 21398 (only send "literal like" objects across isolates spawned using spawnURI

samples/sample_extension/sample_extension.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 <string.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 
 
@@ skipping 75 matching lines @@
       3 == message->value.as_array.length) {
     // Use .as_array and .as_int32 to access the data in the Dart_CObject.
     Dart_CObject* param0 = message->value.as_array.values[0];
     Dart_CObject* param1 = message->value.as_array.values[1];
     Dart_CObject* param2 = message->value.as_array.values[2];
     if (param0->type == Dart_CObject_kInt32 &&
         param1->type == Dart_CObject_kInt32 &&
         param2->type == Dart_CObject_kSendPort) {
       int seed = param0->value.as_int32;
       int length = param1->value.as_int32;
-      reply_port_id = param2->value.as_send_port;
+      reply_port_id = param2->value.as_send_port.id;
       uint8_t* values = randomArray(seed, length);
 
       if (values != NULL) {
         Dart_CObject result;
         result.type = Dart_CObject_kTypedData;
         result.value.as_typed_data.type = Dart_TypedData_kUint8;
         result.value.as_typed_data.values = values;
         result.value.as_typed_data.length = length;
         Dart_PostCObject(reply_port_id, &result);
         free(values);
@@ skipping 72 matching lines @@
     if (strcmp(no_scope_function_list[i].name, cname) == 0) {
       *auto_setup_scope = false;
       result = no_scope_function_list[i].function;
       break;
     }
   }
 
   Dart_ExitScope();
   return result;
 }