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

remoting/protocol/host_control_sender.cc

Index: remoting/protocol/host_control_sender.cc
diff --git a/remoting/protocol/host_control_sender.cc b/remoting/protocol/host_control_sender.cc
index bdf1b95b86ae4a761252e6ccb79ba1c2285916a1..91547a6d5d535b3f5e020cf320d3a16d4e261476 100644
--- a/remoting/protocol/host_control_sender.cc
+++ b/remoting/protocol/host_control_sender.cc
@@ -25,14 +25,6 @@ HostControlSender::HostControlSender(base::MessageLoopProxy* message_loop,
 HostControlSender::~HostControlSender() {
 }
 
-void HostControlSender::BeginSessionRequest(const LocalLoginCredentials* msg,
-                                            const base::Closure& done) {
-  protocol::ControlMessage message;
-  message.mutable_begin_session_request()->mutable_credentials()->CopyFrom(
-      *msg);
-  buffered_writer_->Write(SerializeAndFrameMessage(message), done);
-}
-
 void HostControlSender::Close() {
   buffered_writer_->Close();
 }