Added enum checks since enums are now supported in the IDL

Source/bindings/dart/scripts/dart_utilities.py

Index: Source/bindings/dart/scripts/dart_utilities.py
diff --git a/Source/bindings/dart/scripts/dart_utilities.py b/Source/bindings/dart/scripts/dart_utilities.py
index 3bd0554d07418fba94de8f308a57f28e37fc948e..c9f4fa58a5245edbb4130882e999d6f61c249ebb 100644
--- a/Source/bindings/dart/scripts/dart_utilities.py
+++ b/Source/bindings/dart/scripts/dart_utilities.py
@@ -44,6 +44,14 @@ import v8_types  # Required
 import v8_utilities
 
 
+def _enum_validation_expression(idl_type):
+    # FIXME: Add IdlEnumType, move property to derived type, and remove this check
+    if not idl_type.is_enum:
+        return None
+    return ' || '.join(['((String){param_name}) == "%s"' % enum_value
+                        for enum_value in idl_type.enum_values])
+
+
 def _scoped_name(interface, definition, base_name):
     # partial interfaces are implemented as separate classes, with their members
     # implemented as static member functions
@@ -184,7 +192,7 @@ DartUtilities.conditional_string = v8_utilities.conditional_string
 DartUtilities.cpp_name = v8_utilities.cpp_name
 DartUtilities.deprecate_as = _deprecate_as
 DartUtilities.extended_attribute_value_contains = v8_utilities.extended_attribute_value_contains
-DartUtilities.enum_validation_expression = v8_utilities.enum_validation_expression
+DartUtilities.enum_validation_expression = _enum_validation_expression
 DartUtilities.gc_type = v8_utilities.gc_type
 DartUtilities.generate_native_entry = _generate_native_entry
 DartUtilities.has_extended_attribute = v8_utilities.has_extended_attribute