PairingAuthenticator implementation and plumbing.

remoting/protocol/negotiating_authenticator_base.h

Index: remoting/protocol/negotiating_authenticator_base.h
diff --git a/remoting/protocol/negotiating_authenticator_base.h b/remoting/protocol/negotiating_authenticator_base.h
index 97209c580a00b7d2971d5e11d50f5cda3e9d5dad..1f80967b2d2a8fc33308711fd8825093c1358f4e 100644
--- a/remoting/protocol/negotiating_authenticator_base.h
+++ b/remoting/protocol/negotiating_authenticator_base.h
@@ -71,7 +71,11 @@ class NegotiatingAuthenticatorBase : public Authenticator {
   // Calls |current_authenticator_| to process |message|, passing the supplied
   // |resume_callback|.
   void ProcessMessageInternal(const buzz::XmlElement* message,
-                                      const base::Closure& resume_callback);
+                              const base::Closure& resume_callback);
+
+  const AuthenticationMethod& current_method_for_testing() const {
+    return current_method_;
+  }
 
  protected:
   static const buzz::StaticQName kMethodAttributeQName;