[mojo] Add pickling support for native-only structs

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

 {#  TODO(yzshen): Make these templates more readable. #}
 
 {#  Computes the serialized size for the specified struct.
     |struct| is the struct definition.
     |input_field_pattern| should be a pattern that contains one string
     placeholder, for example, "input->%s", "p_%s". The placeholder will be
     substituted with struct field names to refer to the input fields.
     This macro is expanded to compute seriailized size for both:
     - user-defined structs: the input is an instance of the corresponding struct
       wrapper class.
     - method parameters/response parameters: the input is a list of
       arguments.
     It declares |size| of type size_t to store the resulting size. #}
 {%- macro get_serialized_size(struct, input_field_pattern) -%}
   size_t size = sizeof(internal::{{struct.name}}_Data);
 {%-   for pf in struct.packed.packed_fields_in_ordinal_order if pf.field.kind|is_object_kind %}
-{%-     if pf.field.kind|is_union_kind %}
+{%-     if pf.field.kind|is_native_only_kind %}
+  size += mojo::internal::GetSerializedSizeNative_(
+      {{input_field_pattern|format(pf.field.name)}});
+{%-     elif pf.field.kind|is_union_kind %}
   size += GetSerializedSize_({{input_field_pattern|format(pf.field.name)}}, true);
 {%-     else %}
   size += GetSerializedSize_({{input_field_pattern|format(pf.field.name)}});
 {%-     endif %}
 {%-   endfor %}
 {%- endmacro -%}
 
 {#  Serializes the specified struct.
     |struct| is the struct definition.
     |struct_display_name| is the display name for the struct that can be showed
@@ skipping 19 matching lines @@
 {%-     if kind|is_array_kind %}
   const mojo::internal::ArrayValidateParams {{name}}_validate_params(
       {{kind|get_array_validate_params_ctor_args|indent(10)}});
   mojo::SerializeArray_(std::move({{input_field}}), {{buffer}},
       &{{output}}->{{name}}.ptr, &{{name}}_validate_params);
 {%-     elif kind|is_map_kind %}
   const mojo::internal::ArrayValidateParams {{name}}_validate_params(
       {{kind.value_kind|get_map_validate_params_ctor_args|indent(10)}});
   mojo::SerializeMap_(std::move({{input_field}}), {{buffer}},
       &{{output}}->{{name}}.ptr, &{{name}}_validate_params);
+{%-     elif kind|is_native_only_kind %}
+  mojo::internal::SerializeNative_(
+      {{input_field}}, {{buffer}}, &{{output}}->{{name}}.ptr);
 {%-     elif kind|is_union_kind %}
   internal::{{kind.name}}_Data* {{name}}_ptr = &{{output}}->{{name}};
   SerializeUnion_(std::move({{input_field}}), {{buffer}}, &{{name}}_ptr, true);
 {%-     else %}
   Serialize_(std::move({{input_field}}), {{buffer}}, &{{output}}->{{name}}.ptr);
 {%-     endif %}
 {%-     if not kind|is_nullable_kind %}
   MOJO_INTERNAL_DLOG_SERIALIZATION_WARNING(
 {%-       if kind|is_union_kind %}
       {{output}}->{{name}}.is_null(),
@@ skipping 58 matching lines @@
 {%-   set last_checked_version = 0 %}
 {%-   for pf in struct.packed.packed_fields_in_ordinal_order %}
 {%-     set output_field = output_field_pattern|format(pf.field.name) %}
 {%-     set name = pf.field.name %}
 {%-     set kind = pf.field.kind %}
 {%-     if pf.min_version > last_checked_version %}
 {%-       set last_checked_version = pf.min_version %}
     if ({{input}}->header_.version < {{pf.min_version}})
       break;
 {%-     endif %}
-{%-     if kind|is_object_kind %}
+{%-     if kind|is_native_only_kind %}
+    if (!DeserializeNative_(
+            {{input}}->{{name}}.ptr, &{{output_field}}, {{context}})) {
+      {{success}} = false;
+    }
+{%-     elif kind|is_object_kind %}
 {%-       if kind|is_union_kind %}
     if (!Deserialize_(&{{input}}->{{name}}, &{{output_field}}, {{context}}))
       {{success}} = false;
 {%-       else %}
     if (!Deserialize_({{input}}->{{name}}.ptr, &{{output_field}}, {{context}}))
       {{success}} = false;
 {%-       endif %}
 {%-     elif kind|is_interface_kind %}
     mojo::internal::InterfaceDataToPointer(&{{input}}->{{name}}, &{{output_field}});
 {%-     elif kind|is_interface_request_kind %}
     {{output_field}}.Bind(mojo::MakeScopedHandle(mojo::internal::FetchAndReset(&{{input}}->{{name}})));
 {%-     elif kind|is_any_handle_kind %}
     {{output_field}}.reset(mojo::internal::FetchAndReset(&{{input}}->{{name}}));
 {%-   elif kind|is_associated_interface_kind %}
     mojo::internal::AssociatedInterfaceDataToPtrInfo(&{{input}}->{{name}}, &{{output_field}}, ({{context}})->router.get());
 {%-   elif kind|is_associated_interface_request_kind %}
     mojo::internal::AssociatedInterfaceRequestHelper::SetHandle(
         &{{output_field}},
         ({{context}})->router->CreateLocalEndpointHandle(mojo::internal::FetchAndReset(&{{input}}->{{name}})));
 {%-     elif kind|is_enum_kind %}
     {{output_field}} = static_cast<{{kind|cpp_wrapper_type}}>({{input}}->{{name}});
 {%-     else %}
     {{output_field}} = {{input}}->{{name}};
 {%-     endif %}
 {%-   endfor %}
   } while (false);
 {%- endmacro %}