Mojo: Implement support for |Foo&| mojom syntax

mojo/public/cpp/bindings/no_interface.h

 // 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.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_NO_INTERFACE_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_NO_INTERFACE_H_
 
 #include <assert.h>
 
 #include "mojo/public/cpp/bindings/message.h"
@@ skipping 20 matching lines @@
 
 class NoInterfaceProxy : public NoInterface {
  public:
   explicit NoInterfaceProxy(MessageReceiver* receiver) {}
 };
 
 class NoInterfaceStub : public MessageReceiverWithResponder {
  public:
   NoInterfaceStub() {}
   void set_sink(NoInterface* sink) {}
+  NoInterface* sink() { return NULL; }
   virtual bool Accept(Message* message) MOJO_OVERRIDE;
   virtual bool AcceptWithResponder(Message* message, MessageReceiver* responder)
       MOJO_OVERRIDE;
 };
 
 
 // AnyInterface is for use in cases where any interface would do (e.g., see the
 // Shell::Connect method).
 
 typedef NoInterface AnyInterface;
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_NO_INTERFACE_H_