PairingAuthenticator implementation and plumbing.

remoting/protocol/negotiating_client_authenticator.cc

Index: remoting/protocol/negotiating_client_authenticator.cc
diff --git a/remoting/protocol/negotiating_client_authenticator.cc b/remoting/protocol/negotiating_client_authenticator.cc
index af5d56bc366454d93835eec27ff01be3e51de7bd..1894bc2258a13bf3ee401ad1ab52cb4a33750565 100644
--- a/remoting/protocol/negotiating_client_authenticator.cc
+++ b/remoting/protocol/negotiating_client_authenticator.cc
@@ -12,6 +12,7 @@
 #include "base/logging.h"
 #include "base/strings/string_split.h"
 #include "remoting/protocol/channel_authenticator.h"
+#include "remoting/protocol/pairing_client_authenticator.h"
 #include "remoting/protocol/v2_authenticator.h"
 #include "third_party/libjingle/source/talk/xmllite/xmlelement.h"
 
@@ -19,11 +20,15 @@ namespace remoting {
 namespace protocol {
 
 NegotiatingClientAuthenticator::NegotiatingClientAuthenticator(
+    const std::string& client_pairing_id,
+    const std::string& shared_secret,
     const std::string& authentication_tag,
     const FetchSecretCallback& fetch_secret_callback,
     scoped_ptr<ThirdPartyClientAuthenticator::TokenFetcher> token_fetcher,
     const std::vector<AuthenticationMethod>& methods)
     : NegotiatingAuthenticatorBase(MESSAGE_READY),
+      client_pairing_id_(client_pairing_id),
+      shared_secret_(shared_secret),
       authentication_tag_(authentication_tag),
       fetch_secret_callback_(fetch_secret_callback),
       token_fetcher_(token_fetcher.Pass()),
@@ -81,14 +86,13 @@ scoped_ptr<buzz::XmlElement> NegotiatingClientAuthenticator::GetNextMessage() {
     // If no authentication method has been chosen, see if we can optimistically
     // choose one.
     scoped_ptr<buzz::XmlElement> result;
-    current_authenticator_ = CreatePreferredAuthenticator();
+    CreatePreferredAuthenticator();
     if (current_authenticator_) {
       DCHECK(current_authenticator_->state() == MESSAGE_READY);
       result = GetNextMessageInternal();
     } else {
       result = CreateEmptyAuthenticatorMessage();
     }
-
     // Include a list of supported methods.
     std::stringstream supported_methods(std::stringstream::out);
     for (std::vector<AuthenticationMethod>::iterator it = methods_.begin();
@@ -123,10 +127,15 @@ void NegotiatingClientAuthenticator::CreateAuthenticatorForCurrentMethod(
   }
 }
 
-scoped_ptr<Authenticator>
-NegotiatingClientAuthenticator::CreatePreferredAuthenticator() {
-  NOTIMPLEMENTED();
-  return scoped_ptr<Authenticator>();
+void NegotiatingClientAuthenticator::CreatePreferredAuthenticator() {
+  if (!client_pairing_id_.empty() && !shared_secret_.empty()) {
+    // If the client specified a pairing id and shared secret, then create a
+    // PairingAuthenticator.
+    current_authenticator_.reset(new PairingClientAuthenticator(
+        client_pairing_id_, shared_secret_, fetch_secret_callback_,
+        authentication_tag_));
+    current_method_ = AuthenticationMethod::Spake2Pair();
+  }
 }
 
 void NegotiatingClientAuthenticator::CreateV2AuthenticatorWithSecret(