Mojo C++ bindings: support enum validation.

mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl

 {%- import "interface_macros.tmpl" as interface_macros %}
 {%- import "struct_macros.tmpl" as struct_macros %}
-{%- from "enum_macros.tmpl" import is_valid_enum_def %}
 
 {%- set class_name = interface.name %}
 {%- set proxy_name = interface.name ~ "Proxy" %}
 {%- set namespace_as_string = "%s"|format(namespace|replace(".","::")) %}
 
 {%- macro alloc_params(struct, serialization_context) %}
   bool success = true;
 {%-   for param in struct.packed.packed_fields_in_ordinal_order %}
   {{param.field.kind|cpp_wrapper_type}} p_{{param.field.name}}{};
 {%-   endfor %}
@@ skipping 24 matching lines @@
 
 {#--- Constants #}
 {%-  for constant in interface.constants %}
 {%-   if constant.kind|is_integral_kind %}
 MOJO_STATIC_CONST_MEMBER_DEFINITION const {{constant.kind|cpp_pod_type}} {{interface.name}}::{{constant.name}};
 {%-   else %}
 MOJO_STATIC_CONST_MEMBER_DEFINITION const {{constant.kind|cpp_pod_type}} {{interface.name}}::{{constant.name}} = {{constant|constant_value}};
 {%-   endif %}
 {%- endfor %}
 
-{#--- Enums #}
-{%- for enum in interface.enums %}
-  {{is_valid_enum_def(enum, class_name=interface.name)|indent(2)}}
-{%- endfor %}
-
 {#--- ForwardToCallback definition #}
 {%- for method in interface.methods -%}
 {%-   if method.response_parameters != None %}
 class {{class_name}}_{{method.name}}_ForwardToCallback
     : public mojo::MessageReceiver {
  public:
   {{class_name}}_{{method.name}}_ForwardToCallback(
       const {{class_name}}::{{method.name}}Callback& callback,
       scoped_refptr<mojo::internal::MultiplexRouter> router)
       : callback_(callback), serialization_context_(std::move(router)) {
@@ skipping 257 matching lines @@
     default:
       break;
   }
 
   // Unrecognized message.
   ReportValidationError(
       mojo::internal::VALIDATION_ERROR_MESSAGE_HEADER_UNKNOWN_METHOD);
   return false;
 }
 {%- endif -%}