Mojo: Implement support for |Foo&| mojom syntax

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

 // Copyright 2013 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.
 
 import "sample_import.mojom"
 import "sample_import2.mojom"
 
 [JavaPackage="org.chromium.mojo.bindings.test.sample"]
 module sample {
 
@@ skipping 76 matching lines @@
 };
 
 [Client=ServiceClient]
 interface Service {
   enum BazOptions {
     BAZ_REGULAR = 0,
     BAZ_EXTRA
   };
   const uint8 kFavoriteBaz = 1;
   Frobinate@0(Foo foo@0, BazOptions baz@1, Port port@2);
+  GetPort@1(Port& port @0);
 };
 
 interface ServiceClient {
   DidFrobinate@0(int32 result@0);
 };
 
 // This interface is referenced above where it is defined. It also refers to
 // itself from a method.
 interface Port {
   PostMessage@0(string message_text@0, Port port@1);
 };
 
 }