mash: Update LoginStatus with session state updates

ash/mus/system_tray_delegate_mus.cc

Index: ash/mus/system_tray_delegate_mus.cc
diff --git a/ash/mus/system_tray_delegate_mus.cc b/ash/mus/system_tray_delegate_mus.cc
index c5d0ee173343b85174ca33a6a308d210a787d14b..056c7f088f74c76d796a64cccecd984514bfb0bf 100644
--- a/ash/mus/system_tray_delegate_mus.cc
+++ b/ash/mus/system_tray_delegate_mus.cc
@@ -4,7 +4,9 @@
 
 #include "ash/mus/system_tray_delegate_mus.h"
 
+#include "ash/common/session/session_controller.h"
 #include "ash/common/system/networking_config_delegate.h"
+#include "ash/common/wm_shell.h"
 
 namespace ash {
 namespace {
@@ -34,6 +36,10 @@ SystemTrayDelegateMus::SystemTrayDelegateMus()
 SystemTrayDelegateMus::~SystemTrayDelegateMus() {
 }
 
+LoginStatus SystemTrayDelegateMus::GetUserLoginStatus() const {
+  return WmShell::Get()->session_controller()->GetLoginStatus();
+}
+
 NetworkingConfigDelegate* SystemTrayDelegateMus::GetNetworkingConfigDelegate()
     const {
   return networking_config_delegate_.get();