Refactor of Authenticator to allow it to ProcessMessage asynchronously and then call a callback

remoting/protocol/negotiating_authenticator.h

Index: remoting/protocol/negotiating_authenticator.h
diff --git a/remoting/protocol/negotiating_authenticator.h b/remoting/protocol/negotiating_authenticator.h
index aabbf8827e21f675b99a1e05088b3f7b90dc5867..61b471b559053aee70e74a1b2e5ddf534cb4001e 100644
--- a/remoting/protocol/negotiating_authenticator.h
+++ b/remoting/protocol/negotiating_authenticator.h
@@ -40,7 +40,8 @@ class NegotiatingAuthenticator : public Authenticator {
   // Authenticator interface.
   virtual State state() const OVERRIDE;
   virtual RejectionReason rejection_reason() const OVERRIDE;
-  virtual void ProcessMessage(const buzz::XmlElement* message) OVERRIDE;
+  virtual void ProcessMessage(const buzz::XmlElement* message,
+                              const base::Closure& resume_callback) OVERRIDE;
   virtual scoped_ptr<buzz::XmlElement> GetNextMessage() OVERRIDE;
   virtual scoped_ptr<ChannelAuthenticator>
       CreateChannelAuthenticator() const OVERRIDE;
@@ -50,6 +51,8 @@ class NegotiatingAuthenticator : public Authenticator {
 
   void AddMethod(const AuthenticationMethod& method);
   void CreateAuthenticator(State initial_state);
+  void UpdateState(const base::Closure& resume_callback);
+
   bool is_host_side() const;
 
   // Used only for host authenticators.