Add support for enums within structs and interfaces to mojom.

mojo/public/bindings/generators/js_templates/struct_definition.tmpl

Index: mojo/public/bindings/generators/js_templates/struct_definition.tmpl
diff --git a/mojo/public/bindings/generators/js_templates/struct_definition.tmpl b/mojo/public/bindings/generators/js_templates/struct_definition.tmpl
index 0d8d35cfa4a969c03e41578c337ec89b36cb5bab..1ab7b94f18605c892b0ac577ef9463b612dea601 100644
--- a/mojo/public/bindings/generators/js_templates/struct_definition.tmpl
+++ b/mojo/public/bindings/generators/js_templates/struct_definition.tmpl
@@ -4,6 +4,13 @@
 {%- endfor %}
   }
 
+{#--- Enums #}
+{%- from "enum_definition.tmpl" import enum_def -%}
+{%  for enum in struct.enums %}
+{{  enum_def("%s.%s"|format(struct.name, enum.name), enum)}}
+{%  endfor %}
+
+{#--- Encoding and decoding #}
   {{struct.name}}.encodedSize = codec.kStructHeaderSize + {{struct.packed|payload_size}};
 
   {{struct.name}}.decode = function(decoder) {