Provide chrome the option of learning the debug stub port chosen by nacl.

src/trusted/debug_stub/transport.h

 /*
  * Copyright (c) 2010 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 // This module provides interfaces for an IO stream.  The stream is
 // expected to throw a std::exception if the stream is terminated on
 // either side.
@@ skipping 31 matching lines @@
 class SocketBinding {
  public:
   // Wrap existing socket handle.
   explicit SocketBinding(NaClSocketHandle socket_handle);
   // Bind to the specified TCP port.
   static SocketBinding *Bind(const char *addr);
 
   // Accept a connection on an already-bound TCP port.
   ITransport *AcceptConnection();
 
+  // Get port the socket is bound to.
+  uint16_t GetBoundPort();
+
  private:
   NaClSocketHandle socket_handle_;
 };
 
 }  // namespace port
 
 #endif  // NATIVE_CLIENT_PORT_TRANSPORT_H_