Chromad: Add authentication flow

chromeos/dbus/fake_auth_policy_client.h

Index: chromeos/dbus/fake_auth_policy_client.h
diff --git a/chromeos/dbus/fake_auth_policy_client.h b/chromeos/dbus/fake_auth_policy_client.h
index 55da46fc5df900290bf1dff08ba538988288b59c..ab07e67a40dc5e67984b90a17674565bc19f1a61 100644
--- a/chromeos/dbus/fake_auth_policy_client.h
+++ b/chromeos/dbus/fake_auth_policy_client.h
@@ -22,9 +22,12 @@ class CHROMEOS_EXPORT FakeAuthPolicyClient : public AuthPolicyClient {
   void Init(dbus::Bus* bus) override;
   // AuthPolicyClient overrides.
   void JoinAdDomain(const std::string& machine_name,
-                    const std::string& user,
+                    const std::string& user_principal_name,
                     int password_fd,
                     const JoinCallback& callback) override;
+  void AuthenticateUser(const std::string& user_principal_name,
+                        int password_fd,
+                        const AuthCallback& callback) override;
   void RefreshDevicePolicy(const RefreshPolicyCallback& calllback) override;
   void RefreshUserPolicy(const std::string& account_id,
                          const RefreshPolicyCallback& calllback) override;