Mojo C++ bindings: support enum validation.

mojo/public/tools/bindings/generators/cpp_templates/module-internal.h.tmpl

 // Copyright 2013 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.
 
 {%- if variant -%}
 {%-   set variant_path = "%s-%s"|format(module.path, variant) -%}
 {%- else -%}
 {%-   set variant_path = module.path -%}
 {%- endif -%}
 
@@ skipping 45 matching lines @@
 
 {#--- Internal forward declarations #}
 {%  for struct in structs %}
 class {{struct.name}}_Data;
 {%- endfor %}
 
 {%  for union in unions %}
 class {{union.name}}_Data;
 {%- endfor %}
 
+{#--- Enums #}
+{% from "enum_macros.tmpl" import enum_data_decl -%}
+{%- for enum in enums %}
+  {{enum_data_decl(enum)}}
+{%- endfor %}
+
 #pragma pack(push, 1)
 
 {#--- Unions must be declared first because they can be members of structs #}
 {#--- Union class declarations #}
 {%  for union in unions %}
 {%    include "union_declaration.tmpl" %}
 {%- endfor %}
 
-{#--- Class declarations #}
+{#--- Struct class declarations #}
 {%  for struct in structs %}
 {%    include "struct_declaration.tmpl" %}
 {%- endfor %}
 
+{#--- Interface class declarations. They are needed only when they contain
+    enums. #}
+{%- for interface in interfaces %}
+{%-   if interface.enums %}
+class {{interface.name}}_Data {
+ public:
+{%-     for enum in interface.enums %}
+  {{enum_data_decl(enum)|indent(2)}}
+{%-     endfor %}
+};
+{%-   endif %}
+{%- endfor %}
+
 #pragma pack(pop)
 
 }  // namespace internal
 {%- if variant %}
 }  // namespace {{variant}}
 {%- endif %}
 {%- for namespace in namespaces_as_array|reverse %}
 }  // namespace {{namespace}}
 {%- endfor %}
 
 #endif  // {{header_guard}}