Added enum checks since enums are now supported in the IDL

Source/bindings/dart/scripts/dart_methods.py

Index: Source/bindings/dart/scripts/dart_methods.py
diff --git a/Source/bindings/dart/scripts/dart_methods.py b/Source/bindings/dart/scripts/dart_methods.py
index eb4b14e27af12d150460a69acdbaa0ace5d2a3ca..b700e8939fef3e25b888a9fe202b92da7939a4f0 100644
--- a/Source/bindings/dart/scripts/dart_methods.py
+++ b/Source/bindings/dart/scripts/dart_methods.py
@@ -130,6 +130,10 @@ def argument_context(interface, method, argument, index):
         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,
@@ -138,7 +142,7 @@ def argument_context(interface, method, argument, index):
         '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,