ash: Use enum for SessionController::CycleActiveUser

ash/common/test/test_session_state_delegate.cc

Index: ash/common/test/test_session_state_delegate.cc
diff --git a/ash/common/test/test_session_state_delegate.cc b/ash/common/test/test_session_state_delegate.cc
index 928e6b3aa78c21afa26110492b6efc1bf967821d..265c048705225444ce6dc5a3db832dc810e427e1 100644
--- a/ash/common/test/test_session_state_delegate.cc
+++ b/ash/common/test/test_session_state_delegate.cc
@@ -234,7 +234,7 @@ void TestSessionStateDelegate::SwitchActiveUser(const AccountId& account_id) {
   NOTREACHED() << "Unknown user:" << account_id.GetUserEmail();
 }
 
-void TestSessionStateDelegate::CycleActiveUser(CycleUser cycle_user) {
+void TestSessionStateDelegate::CycleActiveUser(CycleUserDirection direction) {
   SwitchActiveUser(AccountId::FromUserEmail("someone@tray"));
 }