Mojo: Implement support for |Foo&| mojom syntax

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

Index: mojo/public/cpp/bindings/tests/sample_service_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/sample_service_unittest.cc b/mojo/public/cpp/bindings/tests/sample_service_unittest.cc
index 3d0112d2395d8093505cf2daeeb005edcedd44be..b2998a588d0067cea1a8c904c5b50574fa3b6db4 100644
--- a/mojo/public/cpp/bindings/tests/sample_service_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/sample_service_unittest.cc
@@ -275,6 +275,10 @@ class ServiceImpl : public Service {
       Print(depth, "port", port.get());
     }
   }
+
+  virtual void GetPort(mojo::InterfaceRequest<Port> port_request)
+      MOJO_OVERRIDE {
+  }
 };
 
 class ServiceProxyImpl : public ServiceProxy {