Dart: Futures -> Callbacks.

mojo/public/tools/bindings/generators/dart_templates/struct_definition.tmpl

 {#--- Begin #}
 {%- import "encoding_macros.tmpl" as encoding_macros %}
 {%- macro struct_def(struct, typepkg, package) %}
 {#--- Enums #}
 {%- from "enum_definition.tmpl" import enum_def %}
 {%-  for enum in struct.enums %}
 {{enum_def(enum, typepkg, package)}}
 {%-  endfor %}
 
 class {{struct|name}} extends bindings.Struct {
   static const List<bindings.StructDataHeader> kVersions = const [
 {%- for version in struct.versions %}
     const bindings.StructDataHeader({{version.num_bytes}}, {{version.version}}){% if not loop.last %},{% endif %}
 {%- endfor %}
   ];
 
 {#--- Constants #}
 {%-  for constant in struct.constants %}
   static const {{constant.kind|dart_type}} {{constant|name}} = {{constant.resolved_value}};
 {%-  endfor %}
 
 {#--- initDefaults() #}
 {%- for packed_field in struct.packed.packed_fields %}
   {{packed_field.field.kind|dart_type}} {{packed_field.field|name}} = {{packed_field.field|default_value}};
 {%- endfor %}
 
   {{struct|name}}() : super(kVersions.last.size);
 
+  {{struct|name}}.init(
+{%- for packed_field in struct.packed.packed_fields %}
+    {{packed_field.field.kind|dart_type}} this.{{packed_field.field|name}}{% if not loop.last %}, {% endif %}
+{%- endfor %}
+  ) : super(kVersions.last.size);
+
   static {{struct|name}} deserialize(bindings.Message message) {
     var decoder = new bindings.Decoder(message);
     var result = decode(decoder);
     if (decoder.excessHandles != null) {
       decoder.excessHandles.forEach((h) => h.close());
     }
     return result;
   }
 
   static {{struct|name}} decode(bindings.Decoder decoder0) {
@@ skipping 65 matching lines @@
     {%- endfor %}
     return map;
     {%- else %}
     throw new bindings.MojoCodecError(
         'Object containing handles cannot be encoded to JSON.');
     {%- endif %}
   }
 }
 
 {%- endmacro %}