Mojo: NULL -> nullptr in mojo/public/cpp/bindings and also for the bindings generator.

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

 size_t GetSerializedSize_(const {{struct.name}}Ptr& input) {
   if (!input)
     return 0;
   size_t size = sizeof(internal::{{struct.name}}_Data);
 {%- for pf in struct.packed.packed_fields if pf.field.kind|is_object_kind %}
   size += GetSerializedSize_(input->{{pf.field.name}});
 {%- endfor %}
   return size;
 }
 
@@ skipping 27 matching lines @@
         !result->{{pf.field.name}}.is_valid(),
         mojo::internal::VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE,
         "invalid {{pf.field.name}} field in {{struct.name}} struct");
 {%-     endif %}
 {%-   else %}
     result->{{pf.field.name}} = input->{{pf.field.name}};
 {%-   endif %}
 {%- endfor %}
     *output = result;
   } else {
-    *output = NULL;
+    *output = nullptr;
   }
 }
 
 void Deserialize_(internal::{{struct.name}}_Data* input,
                   {{struct.name}}Ptr* output) {
   if (input) {
     {{struct.name}}Ptr result({{struct.name}}::New());
 {%- for pf in struct.packed.packed_fields %}
 {%-   if pf.field.kind|is_object_kind %}
     Deserialize_(input->{{pf.field.name}}.ptr, &result->{{pf.field.name}});
 {%-   elif pf.field.kind|is_interface_kind %}
     if (input->{{pf.field.name}}.is_valid())
       result->{{pf.field.name}}.Bind(mojo::MakeScopedHandle(mojo::internal::FetchAndReset(&input->{{pf.field.name}})));
 {%-   elif pf.field.kind|is_any_handle_kind %}
     result->{{pf.field.name}}.reset(mojo::internal::FetchAndReset(&input->{{pf.field.name}}));
 {%-   elif pf.field.kind|is_enum_kind %}
     result->{{pf.field.name}} = static_cast<{{pf.field.kind|cpp_wrapper_type}}>(
       input->{{pf.field.name}});
 {%-   else %}
     result->{{pf.field.name}} = input->{{pf.field.name}};
 {%-   endif %}
 {%- endfor %}
     *output = result.Pass();
   } else {
     output->reset();
   }
 }