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

class {{interface.name}}Stub : public mojo::MessageReceiverWithResponder {
 public:
  {{interface.name}}Stub();
  void set_sink({{interface.name}}* sink) { sink_ = sink; }
  {{interface.name}}* sink() { return sink_; }

  virtual bool Accept(mojo::Message* message) override;
  virtual bool AcceptWithResponder(mojo::Message* message,
                                   mojo::MessageReceiver* responder) override;

 private:
  {{interface.name}}* sink_;
};