[Sync] Propagate XMPP auth errors to SyncNotifierObservers

jingle/notifier/communicator/single_login_attempt.h

Index: jingle/notifier/communicator/single_login_attempt.h
diff --git a/jingle/notifier/communicator/single_login_attempt.h b/jingle/notifier/communicator/single_login_attempt.h
index 1e0332da39b85b5877d6368a8851699712a8cc52..d0813ee9b881846211e9d3ab4ac93f7612a8ece9 100644
--- a/jingle/notifier/communicator/single_login_attempt.h
+++ b/jingle/notifier/communicator/single_login_attempt.h
@@ -26,12 +26,17 @@ struct ServerInformation;
 // login attempt.
 class SingleLoginAttempt : public XmppConnection::Delegate {
  public:
+  // At most one delegate method will be called, depending on the
+  // result of the login attempt.  After the delegate method is
+  // called, this class won't do anything anymore until it is
+  // destroyed, at which point it will disconnect if necessary.
   class Delegate {
    public:
     virtual void OnConnect(
         base::WeakPtr<buzz::XmppTaskParentInterface> base_task) = 0;
     virtual void OnNeedReconnect() = 0;
     virtual void OnRedirect(const ServerInformation& redirect_server) = 0;
+    virtual void OnRejectedCredentials() = 0;
 
    protected:
     virtual ~Delegate();