[mojo-bindings] Support reuse of native enum classes

mojo/public/tools/bindings/pylib/mojom/parse/translate.py

Index: mojo/public/tools/bindings/pylib/mojom/parse/translate.py
diff --git a/mojo/public/tools/bindings/pylib/mojom/parse/translate.py b/mojo/public/tools/bindings/pylib/mojom/parse/translate.py
index e457f994b0acd7d7913a7b5422dd08b9d21af37b..36bd68a48128129304580e3589661c3219fd981f 100644
--- a/mojo/public/tools/bindings/pylib/mojom/parse/translate.py
+++ b/mojo/public/tools/bindings/pylib/mojom/parse/translate.py
@@ -98,8 +98,9 @@ def _EnumToDict(enum):
     return data
 
   assert isinstance(enum, ast.Enum)
-  data = {'name': enum.name,
-          'fields': map(EnumValueToDict, enum.enum_value_list)}
+  data = { 'name': enum.name, 'native_only': enum.enum_value_list is None }
+  if not data['native_only']:
+    data['fields'] = map(EnumValueToDict, enum.enum_value_list)
   _AddOptional(data, 'attributes', _AttributeListToDict(enum.attribute_list))
   return data