Mojo: Simplify object serialization

mojo/public/bindings/generators/cpp_templates/params_definition.tmpl

Index: mojo/public/bindings/generators/cpp_templates/params_definition.tmpl
diff --git a/mojo/public/bindings/generators/cpp_templates/params_definition.tmpl b/mojo/public/bindings/generators/cpp_templates/params_definition.tmpl
index 32d9bab950668635b6465987cc8b0f59071e1579..b21f537dd4b3f3efddf009ec01329e116931a374 100644
--- a/mojo/public/bindings/generators/cpp_templates/params_definition.tmpl
+++ b/mojo/public/bindings/generators/cpp_templates/params_definition.tmpl
@@ -15,9 +15,23 @@ class {{class_name}} {
 {#--- Getters -#}
 {{ struct_macros.getters(struct) }}
 
- private:
-  friend class mojo::internal::ObjectTraits<{{class_name}}>;
+  void CloseHandles() {
+{%- for pf in struct.packed.packed_fields if pf.field.kind|is_object_kind %}
+    if ({{pf.field.name}}_.ptr)
+      {{pf.field.name}}_.ptr->CloseHandles();
+{%- endfor %}
+  }
+
+  void EncodePointersAndHandles(std::vector<mojo::Handle>* handles) {
+    {{ struct_macros.encodes(struct)|indent(4) }}
+  }
 
+  bool DecodePointersAndHandles(mojo::Message* message) {
+    {{ struct_macros.decodes(struct)|indent(4) }}
+    return true;
+  }
+
+ private:
   {{class_name}}() {
     _header_.num_bytes = sizeof(*this);
     _header_.num_fields = 3;