cros: Use SessionController to enable system tray settings / notifications tray

ash/system/tray/system_tray_delegate.cc

Index: ash/system/tray/system_tray_delegate.cc
diff --git a/ash/system/tray/system_tray_delegate.cc b/ash/system/tray/system_tray_delegate.cc
index f1ff267679884ef5f3a5c72e57a246f756ac3639..10669a0a5e247c766fa57f3cfa42f5529ca0eb96 100644
--- a/ash/system/tray/system_tray_delegate.cc
+++ b/ash/system/tray/system_tray_delegate.cc
@@ -51,14 +51,6 @@ bool SystemTrayDelegate::IsUserChild() const {
   return false;
 }
 
-bool SystemTrayDelegate::ShouldShowSettings() const {
-  return false;
-}
-
-bool SystemTrayDelegate::ShouldShowNotificationTray() const {
-  return false;
-}
-
 void SystemTrayDelegate::ShowEnterpriseInfo() {}
 
 void SystemTrayDelegate::ShowUserLogin() {}