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

remoting/protocol/client_stub.h

Index: remoting/protocol/client_stub.h
diff --git a/remoting/protocol/client_stub.h b/remoting/protocol/client_stub.h
index 49b6740fe3225a916b83c9b07d7a340242084718..ef2f8fe9344c209e0e0e85f39b11e74aef175231 100644
--- a/remoting/protocol/client_stub.h
+++ b/remoting/protocol/client_stub.h
@@ -16,16 +16,13 @@
 namespace remoting {
 namespace protocol {
 
-class LocalLoginStatus;
-class NotifyResolutionRequest;
-
 class ClientStub {
  public:
   ClientStub() {}
   virtual ~ClientStub() {}
 
-  virtual void BeginSessionResponse(const LocalLoginStatus* msg,
-                                    const base::Closure& done) = 0;
+  // Currently we don't use the control channel for anything. Add new
+  // message handlers here when necessary.
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ClientStub);