[mojo-bindings] Support reuse of native enum classes

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

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Translates parse tree to Mojom IR."""
 
 import re
 
 from . import ast
 
@@ skipping 80 matching lines @@
 def _EnumToDict(enum):
   def EnumValueToDict(enum_value):
     assert isinstance(enum_value, ast.EnumValue)
     data = {'name': enum_value.name}
     _AddOptional(data, 'value', enum_value.value)
     _AddOptional(data, 'attributes',
                  _AttributeListToDict(enum_value.attribute_list))
     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
 
 def _ConstToDict(const):
   assert isinstance(const, ast.Const)
   return {'name': const.name,
           'kind': _MapKind(const.typename),
           'value': const.value}
 
 
@@ skipping 103 matching lines @@
     self.mojom['constants'] = \
         _MapTreeForType(_ConstToDict, tree.definition_list, ast.Const, name)
     _AddOptional(self.mojom, 'attributes',
                  _AttributeListToDict(tree.module.attribute_list)
                      if tree.module else None)
     return self.mojom
 
 
 def Translate(tree, name):
   return _MojomBuilder().Build(tree, name)