Remove old Authentication code that we don't use or need.

remoting/protocol/host_control_sender.h

Index: remoting/protocol/host_control_sender.h
diff --git a/remoting/protocol/host_control_sender.h b/remoting/protocol/host_control_sender.h
index b1e15b4189024ebbb40777a9e1905a01ae4136d2..4a92bf321d875de5f48130f41b9dac43abc15a1c 100644
--- a/remoting/protocol/host_control_sender.h
+++ b/remoting/protocol/host_control_sender.h
@@ -39,9 +39,6 @@ class HostControlSender : public HostStub {
                              net::Socket* socket);
   virtual ~HostControlSender();
 
-  virtual void BeginSessionRequest(
-      const LocalLoginCredentials* credentials, const base::Closure& done);
-
   // Stop writing. Must be called on the network thread when the
   // underlying socket is being destroyed.
   void Close();