Mojo C++ bindings: custom type mapping of map

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

 {{struct.name}}DataView::{{struct.name}}DataView(
     internal::{{struct.name}}_Data*  data,
     mojo::internal::SerializationContext* context)
     : data_(data), context_(context) {
   DCHECK(data_);
 }
 
 {%- for pf in struct.packed.packed_fields_in_ordinal_order %}
 {%-   set kind = pf.field.kind -%}
 {%-   set name = pf.field.name -%}
-{%-   if kind|is_struct_kind or kind|is_array_kind or kind|is_string_kind %}
+{%-   if kind|is_struct_kind or kind|is_array_kind or kind|is_string_kind or
+         kind|is_map_kind %}
 {#-     Does nothing. They are already defined in the class declaration. #}
-{%-   elif kind|is_map_kind %}
-bool {{struct.name}}DataView::Read{{name|under_to_camel}}(
-    {{kind|cpp_wrapper_type}}* value) {
-{%-     if pf.min_version != 0 %}
-    auto pointer = data_->header_.version >= {{pf.min_version}}
-                   ? data_->{{name}}.ptr : nullptr;
-{%-     else %}
-    auto pointer = data_->{{name}}.ptr;
-{%-     endif %}
-  return mojo::internal::Deserialize<{{kind|unmapped_type_for_serializer}}>(
-      pointer, value, context_);
-}
 
 {%-   elif kind|is_union_kind %}
 bool {{struct.name}}DataView::Read{{name|under_to_camel}}(
     {{kind|cpp_wrapper_type}}* value) {
 {%-     if pf.min_version != 0 %}
     auto pointer = data_->header_.version >= {{pf.min_version}}
                    ? &data_->{{name}} : nullptr;
 {%-     else %}
     auto pointer = &data_->{{name}};
 {%-     endif %}
@@ skipping 63 matching lines @@
 {{kind|cpp_wrapper_type}} {{struct.name}}DataView::{{name}}() const {
 {%-     if pf.min_version != 0 %}
   if (data_->header_.version < {{pf.min_version}})
     return {{kind|cpp_wrapper_type}}{};
 {%-     endif %}
   return static_cast<{{kind|cpp_wrapper_type}}>(data_->{{name}});
 }
 {%-   endif %}
 {%- endfor %}