[mojo] Support native types with mojom wire format

mojo/public/interfaces/bindings/tests/test_native_types.mojom

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module mojo.test;
 
+import "mojo/public/interfaces/bindings/tests/rect.mojom";
+
 // Used to verify that structs can be declared with no body in mojom.
 
 [native=True]
 struct PickledStruct;
 
 interface PicklePasser {
   PassPickle(PickledStruct pickle) => (PickledStruct passed);
 };
+
+// Used to verify support for native serialization of mojom-defined structs.
+// This is tested with a typemap applied to the Rect type from rect.mojom.
+
+interface RectService {
+  AddRect(Rect r);
+  GetLargestRect() => (Rect largest);
+};
+