Pass the desktop session ID to the remoting network process.

remoting/host/desktop_session_win.h

 // Copyright (c) 2012 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 REMOTING_HOST_DESKTOP_SESSION_WIN_H_
 #define REMOTING_HOST_DESKTOP_SESSION_WIN_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 113 matching lines @@
 
   // True if |this| is subsribed to receive session attach/detach notifications.
   bool monitoring_notifications_;
 
   // Used to report an error if the session attach notification does not arrives
   // for too long.
   base::OneShotTimer session_attach_timer_;
 
   base::Time last_timestamp_;
 
+  // The id of the current desktop session being remoted or UINT32_MAX if no
+  // session exists.
+  int session_id_ = UINT32_MAX;
+
   DISALLOW_COPY_AND_ASSIGN(DesktopSessionWin);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_DESKTOP_SESSION_WIN_H_