Handle pairing_client_id in the negotiating authenticators.

remoting/protocol/pairing_client_authenticator.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_PROTOCOL_PAIRING_CLIENT_AUTHENTICATOR_H_
 #define REMOTING_PROTOCOL_PAIRING_CLIENT_AUTHENTICATOR_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "remoting/protocol/client_authentication_config.h"
 #include "remoting/protocol/pairing_authenticator_base.h"
 
 namespace remoting {
 namespace protocol {
 
 class PairingClientAuthenticator : public PairingAuthenticatorBase {
  public:
   PairingClientAuthenticator(
       const ClientAuthenticationConfig& client_auth_config,
       const CreateBaseAuthenticatorCallback&
           create_base_authenticator_callback);
   ~PairingClientAuthenticator() override;
 
+  // Start() or StartPaired() must be called after the authenticator is created.
+  // Start() handles both cases when pairing exists and when it doesn't.
+  // StartPaired() can only be used when pairing exists (i.e. client_id and
+  // pairing_secret are set in the |client_auth_config|). It is used to
+  // initialize the authenticator synchronously in
+  // NegotiatingClientAuthentitcator, while Start() may be executed
+  // asynchronously to fetch the PIN.
+  void Start(State initial_state, const base::Closure& resume_callback);
+  void StartPaired(State initial_state);
+
   // Authenticator interface.
   State state() const override;
 
  private:
   // PairingAuthenticatorBase overrides.
   void CreateSpakeAuthenticatorWithPin(
       State initial_state,
       const base::Closure& resume_callback) override;
-  void AddPairingElements(buzz::XmlElement* message) override;
 
   void OnPinFetched(State initial_state,
                     const base::Closure& resume_callback,
                     const std::string& pin);
 
   ClientAuthenticationConfig client_auth_config_;
   CreateBaseAuthenticatorCallback create_base_authenticator_callback_;
 
-  // Set to true after client_id is sent to the host.
-  bool sent_client_id_ = false;
-
   // Set to true if a PIN-based authenticator has been requested but has not
   // yet been set.
   bool waiting_for_pin_ = false;
 
   base::WeakPtrFactory<PairingClientAuthenticator> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PairingClientAuthenticator);
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_PAIRING_AUTHENTICATOR_H_