Implement unions as members of structs.

mojo/public/cpp/bindings/tests/struct_unittest.cc

 // Copyright 2014 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.
 
 #include <string.h>
 
 #include "mojo/public/cpp/bindings/lib/fixed_buffer.h"
 #include "mojo/public/cpp/environment/environment.h"
 #include "mojo/public/cpp/system/message_pipe.h"
 #include "mojo/public/interfaces/bindings/tests/test_structs.mojom.h"
@@ skipping 400 matching lines @@
     MultiVersionStructPtr input = MakeMultiVersionStruct();
     MultiVersionStructV0Ptr expected_output(MultiVersionStructV0::New());
     expected_output->f_int32 = 123;
 
     MultiVersionStructV0Ptr output =
         SerializeAndDeserialize<MultiVersionStructV0Ptr>(input.Pass());
     EXPECT_TRUE(output);
     EXPECT_TRUE(output->Equals(*expected_output));
   }
 }
-
 }  // namespace test
 }  // namespace mojo