Mojo: more idiomatic C++ bindings

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

 {%- import "struct_macros.tmpl" as struct_macros %}
 {%- set class_name = struct.name ~ "_Data" %}
 
 // static
-{{class_name}}* {{class_name}}::New(mojo::Buffer* buf, mojo::Buffer::Destructor dtor) {
-  return new (buf->Allocate(sizeof({{class_name}}), dtor)) {{class_name}}();
+{{class_name}}* {{class_name}}::New(mojo::internal::Buffer* buf) {
+  return new (buf->Allocate(sizeof({{class_name}}))) {{class_name}}();
 }
 
 {{class_name}}::{{class_name}}() {
-  _header_.num_bytes = sizeof(*this);
-  _header_.num_fields = {{struct.packed.packed_fields|length}};
-}
-
-size_t {{class_name}}::ComputeSize() const {
-  size_t result = sizeof(*this);
-{%- for pf in struct.packed.packed_fields if pf.field.kind|is_object_kind %}
-  if ({{pf.field.name}}_.ptr)
-    result += {{pf.field.name}}_.ptr->ComputeSize();
-{%- endfor %}
-  return result;
-}
-
-{{class_name}}* {{class_name}}::Clone(mojo::Buffer* buf) const {
-  {{class_name}}* clone = New(buf);
-  memcpy(clone, this, sizeof(*this));
-{%- for pf in struct.packed.packed_fields if pf.field.kind|is_object_kind %}
-  if ({{pf.field.name}}_.ptr)
-    clone->set_{{pf.field.name}}({{pf.field.name}}_.ptr->Clone(buf));
-{%- endfor %}
-{%- for pf in struct.packed.packed_fields if pf.field.kind|is_handle_kind %}
-  mojo::internal::ResetIfNonNull({{pf.field.name}}());
-{%- endfor %}
-  return clone;
-}
-
-void {{class_name}}::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 %}
-{%- if struct|is_struct_with_handles %}
-  {{struct.name}}_Data_Destructor(this);
-{%- endif %}
+  header_.num_bytes = sizeof(*this);
+  header_.num_fields = {{struct.packed.packed_fields|length}};
 }
 
 void {{class_name}}::EncodePointersAndHandles(
     std::vector<mojo::Handle>* handles) {
   {{ struct_macros.encodes(struct)|indent(2) }}
 }
 
 bool {{class_name}}::DecodePointersAndHandles(mojo::Message* message) {
   {{ struct_macros.decodes(struct)|indent(2) }}
   return true;
 }