Mojo C++ bindings: disallow copy and assign for generated classes when necessary.

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

 {% from "enum_macros.tmpl" import enum_decl -%}
 
 class {{export_attribute}} {{struct.name}} {
  public:
   using DataView = {{struct.name}}DataView;
   using Data_ = internal::{{struct.name}}_Data;
 
 {#--- Enums #}
 {%- for enum in struct.enums -%}
 {%-   if enum|is_native_only_kind %}
@@ skipping 57 matching lines @@
         {{struct.name}}Ptr, {{serialization_result_type}}>(
             input, output);
   }
 
 {#--- Struct members #}
 {%  for field in struct.fields %}
 {%-   set type = field.kind|cpp_wrapper_type %}
 {%-   set name = field.name %}
   {{type}} {{name}};
 {%- endfor %}
+
+{%- if struct|contains_move_only_members %}
+ private:
+  DISALLOW_COPY_AND_ASSIGN({{struct.name}});
+{%- endif %}
 };