Added enum checks since enums are now supported in the IDL

Source/bindings/dart/scripts/dart_methods.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 112 matching lines @@
     default_value = argument.default_cpp_value
     if context['has_default']:
         default_value = (argument.default_cpp_value or
             dart_types.default_cpp_value_for_cpp_type(idl_type))
     # FIXMEDART: handle the drift between preprocessed type names in 1847 and
     # 1985 dartium builds in a more generic way.
     if preprocessed_type == 'unrestricted float':
         preprocessed_type = 'float'
     if preprocessed_type == 'unrestricted double':
         preprocessed_type = 'double'
+
+    dart_enum_expression = idl_type.enum_validation_expression
+    if dart_enum_expression:
+        dart_enum_expression = dart_enum_expression.format(param_name=argument.name)
     context.update({
         'cpp_type': idl_type.cpp_type_args(extended_attributes=extended_attributes,
                                            raw_type=True,
                                            used_in_cpp_sequence=use_heap_vector_type),
         'cpp_value': this_cpp_value,
         'local_cpp_type': local_cpp_type,
         # FIXME: check that the default value's type is compatible with the argument's
         'default_value': default_value,
-        'enum_validation_expression': idl_type.enum_validation_expression,
+        'enum_validation_expression': dart_enum_expression,
         'preprocessed_type': preprocessed_type,
         'is_array_or_sequence_type': not not idl_type.native_array_element_type,
         'is_strict_type_checking': 'DartStrictTypeChecking' in extended_attributes,
         'is_dictionary': idl_type.is_dictionary or idl_type.base_type == 'Dictionary',
         'vector_type': 'WillBeHeapVector' if use_heap_vector_type else 'Vector',
         'dart_set_return_value_for_main_world': dart_set_return_value(interface.name, method,
                                                                       this_cpp_value, for_main_world=True),
         'dart_set_return_value': dart_set_return_value(interface.name, method, this_cpp_value),
         'arg_index': arg_index,
         'dart_value_dictionary_cpp_value': dart_dictionary_value_argument(argument, arg_index),
@@ skipping 121 matching lines @@
     # There is also some logic in systemnative.py to force a null check
     # for the useCapture argument of those same methods that we may need to
     # pull over.
     null_check = ((argument.is_optional and idl_type.is_callback_interface) or
                   (idl_type.name == 'Dictionary') or
                   (argument.default_value and argument.default_value.is_null))
 
     return idl_type.dart_value_to_local_cpp_value(
         extended_attributes, name, null_check, has_type_checking_interface,
         index=index, auto_scope=auto_scope)