Implement python mojo bindings unions.

mojo/public/tools/bindings/generators/python_templates/module_macros.tmpl

 # 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.
 
 {%- macro enum_values(enum) -%}
 [
 {% for field in enum.fields %}
   ('{{field.name}}', {{field.resolved_value}}),
 {% endfor %}
 ]
@@ skipping 19 matching lines @@
   'fields': [
 {%  for byte in struct.bytes %}
 {%    if byte.packed_fields %}
     {{byte|field_group}},
 {%    endif %}
 {% endfor %}
   ],
 {% endif %}
 }
 {%- endmacro -%}
+
+{%- macro union_descriptor(union) -%}
+{
+  'fields': [
+{%    for field in union.fields %}
+      {{field|union_field_descriptor}},

[qsr, 2015/07/17 10:53:58]

Alignemtn is still wrong. The issue was with the for. You want:
{% for field in union.fields %}
  {{field|union_field_descriptor}},
{% endfor %}

See enum_values for example.

[azani, 2015/07/17 20:38:16]

Thanks for the clarification.

+{%    endfor %}
+  ],
+}
+{%- endmacro -%}