Mojo C++ bindings: add a new mode to generator to use native STL/WTF types

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

 {%- import "interface_macros.tmpl" as interface_macros %}
 class {{interface.name}}Proxy;
 class {{interface.name}}Stub;
 
 class {{interface.name}}RequestValidator;
 {%- if interface|has_callbacks %}
 class {{interface.name}}ResponseValidator;
 {%- endif %}
 
 class {{interface.name}} {
@@ skipping 36 matching lines @@
   virtual ~{{interface.name}}() {}
 
 {%- for method in interface.methods %}
 {%    if method.response_parameters != None %}
 {%-     if method.sync %}
   // Sync method. This signature is used by the client side; the service side
   // should implement the signature with callback below.
   virtual bool {{method.name}}({{interface_macros.declare_sync_method_params("", method)}});
 {%-     endif %}
 
-  using {{method.name}}Callback = {{interface_macros.declare_callback(method, for_blink)}};
+  using {{method.name}}Callback = {{interface_macros.declare_callback(method,
+      for_blink, use_new_wrapper_types)}};
 {%-   endif %}
   virtual void {{method.name}}({{interface_macros.declare_request_params("", method)}}) = 0;
 {%- endfor %}
 };