Mojo C++ bindings: custom type mapping of map

mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.h

Index: mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.h
diff --git a/mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.h b/mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.h
index c4a429531ce7a33f52b6d3c84c548db82cd9883f..90fd92d2447ce1f4fd1c354ceac9a9c4f3b13342 100644
--- a/mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.h
+++ b/mojo/public/cpp/bindings/tests/struct_with_traits_impl_traits.h
@@ -73,6 +73,11 @@ struct StructTraits<test::StructWithTraits, test::StructWithTraitsImpl> {
       const test::StructWithTraitsImpl& value) {
     return value.get_struct_array();
   }
+
+  static const std::map<std::string, test::NestedStructWithTraitsImpl>&
+  f_struct_map(const test::StructWithTraitsImpl& value) {
+    return value.get_struct_map();
+  }
 };
 
 template <>