Make the fuchsia mojo/public repo the source of truth.

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

-{%- import "interface_macros.tmpl" as interface_macros %}
-class {{interface.name}}Proxy
-    : public {{interface.name}},
-      public mojo::internal::ControlMessageProxy {
- public:
-  explicit {{interface.name}}Proxy(mojo::MessageReceiverWithResponder* receiver);
-
-{%- for method in interface.methods %}
-  void {{method.name}}(
-      {{interface_macros.declare_request_params("", method)}}
-  ) override;
-{%- endfor %}
-};