ash: Use session_manager::SessionState

ash/mus/shell_delegate_mus.cc

Index: ash/mus/shell_delegate_mus.cc
diff --git a/ash/mus/shell_delegate_mus.cc b/ash/mus/shell_delegate_mus.cc
index 8dd3c02d7c40237a40d72eb246c7dc657dceac74..41488306a8438cd803d3624a2b9aaf424b454ef9 100644
--- a/ash/mus/shell_delegate_mus.cc
+++ b/ash/mus/shell_delegate_mus.cc
@@ -58,7 +58,7 @@ class SessionStateDelegateStub : public SessionStateDelegate {
     screen_locked_ = false;
   }
   bool IsUserSessionBlocked() const override { return false; }
-  SessionState GetSessionState() const override { return SESSION_STATE_ACTIVE; }
+  SessionState GetSessionState() const override { return SessionState::ACTIVE; }
   const user_manager::UserInfo* GetUserInfo(UserIndex index) const override {
     return user_info_.get();
   }