Added Aura notification that relaunch and powerwash is required in case of downgrade.

ash/system/tray/default_system_tray_delegate.cc

Index: ash/system/tray/default_system_tray_delegate.cc
diff --git a/ash/system/tray/default_system_tray_delegate.cc b/ash/system/tray/default_system_tray_delegate.cc
index fda48075ec2a16db115abc50ec9a13f781bd3346..7cc9608fe672d32810517a7975c83959ce0216cb 100644
--- a/ash/system/tray/default_system_tray_delegate.cc
+++ b/ash/system/tray/default_system_tray_delegate.cc
@@ -90,8 +90,12 @@ bool DefaultSystemTrayDelegate::IsUserSupervised() const {
   return false;
 }
 
-bool DefaultSystemTrayDelegate::SystemShouldUpgrade() const {
-  return true;
+void DefaultSystemTrayDelegate::GetSystemUpdateInfo(UpdateInfo* info) const {
+  if (!info)
+    return;

[stevenjb, 2014/10/02 15:33:55]

This should just be DCHECK(info) - there is no reason to call this with a NULL
info.

[ygorshenin1, 2014/10/02 15:40:21]

Done.

+  info->severity = UpdateInfo::UPDATE_NORMAL;
+  info->update_required = true;
+  info->factory_reset_required = false;
 }
 
 base::HourClockType DefaultSystemTrayDelegate::GetHourClockType() const {