Generate a templated Clone method for all mojo structs.

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

 // static
 {{struct.name}}Ptr {{struct.name}}::New() {
   {{struct.name}}Ptr rv;
   mojo::internal::StructHelper<{{struct.name}}>::Initialize(&rv);
   return rv;
 }
 
 {{struct.name}}::{{struct.name}}()
 {%- for field in struct.fields %}
     {% if loop.first %}:{% else %} {% endif %} {{field.name}}({{field|default_value}}){% if not loop.last %},{% endif %}
 {%- endfor %} {
 }
 
 {{struct.name}}::~{{struct.name}}() {
 }
 
 {%  if struct|is_cloneable_kind %}
 {{struct.name}}Ptr {{struct.name}}::Clone() const {
   {{struct.name}}Ptr rv(New());
 {%-   for field in struct.fields %}
-{%-     if field.kind|is_object_kind and not field.kind|is_string_kind %}
+{%-     if field.kind|is_object_kind and not field.kind|is_string_kind and not field.kind|is_typemapped_kind%}

[yzshen1, 2016/05/26 16:24:14]

style nit: 
- one space before %}
- break the line into 2 lines so that it doesn't exceed 80 chars. (I know we
don't strictly follow this rule in tmpl files, but nice to do it whenever
possible.)

[Sam McNally, 2016/05/27 02:57:40]

Done.

   rv->{{field.name}} = {{field.name}}.Clone();
 {%-     else %}
   rv->{{field.name}} = {{field.name}};
 {%-     endif %}
 {%-   endfor %}
   return rv;
 }
 {%  endif %}