Fix for issue 12489.

tools/dom/scripts/systemnative.py

 #!/usr/bin/python
 # 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.
 
 """This module provides shared functionality for the systems to generate
 native binding from the IDL database."""
 
 import emitter
 import os
@@ skipping 949 matching lines @@
           '            return;\n',
           NATIVE_TYPE=return_type_info.native_type(),
           FUNCTION_CALL=function_call)
         value_expression = 'result'
       else:
         value_expression = function_call
 
       # Generate to Dart conversion of C++ value.
       if return_type_info.dart_type() == 'bool':
         set_return_value = 'Dart_SetBooleanReturnValue(args, %s)' % (value_expression)
-      elif return_type_info.dart_type() == 'int':
+      elif return_type_info.dart_type() == 'int' and return_type_info.native_type() == 'int':
         set_return_value = 'Dart_SetIntegerReturnValue(args, %s)' % (value_expression)
       elif return_type_info.dart_type() == 'double':
         set_return_value = 'Dart_SetDoubleReturnValue(args, %s)' % (value_expression)
       elif return_type_info.dart_type() == 'String':
         if ext_attrs and 'TreatReturnedNullStringAs' in ext_attrs:
           set_return_value = 'DartUtilities::setDartStringReturnValueWithNullCheck(args, %s)' % (value_expression)
         else:
           set_return_value = 'DartUtilities::setDartStringReturnValue(args, %s)' % (value_expression)
       else:
         to_dart_conversion = return_type_info.to_dart_conversion(value_expression, self._interface.id, ext_attrs)
@@ skipping 135 matching lines @@
             '    if (Dart_NativeFunction func = $CLASS_NAME::resolver(name, argumentCount))\n'
             '        return func;\n',
             CLASS_NAME=os.path.splitext(os.path.basename(path))[0])
 
 def _IsOptionalStringArgumentInInitEventMethod(interface, operation, argument):
   return (
       interface.id.endswith('Event') and
       operation.id.startswith('init') and
       argument.ext_attrs.get('Default') == 'Undefined' and
       argument.type.id == 'DOMString')