Add gnubby authentication to remoting host

remoting/host/chromoting_host.h

Index: remoting/host/chromoting_host.h
diff --git a/remoting/host/chromoting_host.h b/remoting/host/chromoting_host.h
index 3e1fa741ccd7bf466c6e8a816bd3bd62086e4805..82b6e7fa3b45f49b5207ecae598616382cd1de7a 100644
--- a/remoting/host/chromoting_host.h
+++ b/remoting/host/chromoting_host.h
@@ -109,6 +109,9 @@ class ChromotingHost : public base::NonThreadSafe,
   // Takes immediate effect if clients are already connected.
   void SetEnableCurtaining(bool enable);
 
+  // Enables/disables gnubby auth forwarding.
+  void SetEnableGnubbyAuth(bool enable);
+
   // Sets the maximum duration of any session. By default, a session has no
   // maximum duration.
   void SetMaximumSessionDuration(const base::TimeDelta& max_session_duration);
@@ -200,6 +203,9 @@ class ChromotingHost : public base::NonThreadSafe,
   // The maximum duration of any session.
   base::TimeDelta max_session_duration_;
 
+  // True if gnubby auth is enabled.
+  bool enable_gnubby_auth_;
+
   // The pairing registry for PIN-less authentication.
   scoped_refptr<protocol::PairingRegistry> pairing_registry_;