Remove update icon after user confirms download

ash/system/tray/system_tray_notifier.h

Index: ash/system/tray/system_tray_notifier.h
diff --git a/ash/system/tray/system_tray_notifier.h b/ash/system/tray/system_tray_notifier.h
index 0373448e73340b463c11bee9166753fdc4b0813e..89ff134be4fb31fa41728e88eb70aa4496dfde6b 100644
--- a/ash/system/tray/system_tray_notifier.h
+++ b/ash/system/tray/system_tray_notifier.h
@@ -31,6 +31,7 @@ class ScreenShareObserver;
 class StatusAreaFocusObserver;
 class TracingObserver;
 class VirtualKeyboardObserver;
+class UpdateObserver;
 
 namespace mojom {
 enum class UpdateSeverity;
@@ -120,6 +121,11 @@ class ASH_EXPORT SystemTrayNotifier {
   void RemoveTracingObserver(TracingObserver* observer);
   void NotifyTracingModeChanged(bool value);
 
+  // Update.
+  void AddUpdateObserver(UpdateObserver* observer);
+  void RemoveUpdateObserver(UpdateObserver* observer);
+  void NotifyUpdateOverCellularTargetSet(bool success);
+
   // Virtual keyboard.
   void AddVirtualKeyboardObserver(VirtualKeyboardObserver* observer);
   void RemoveVirtualKeyboardObserver(VirtualKeyboardObserver* observer);
@@ -140,6 +146,7 @@ class ASH_EXPORT SystemTrayNotifier {
   base::ObserverList<ScreenShareObserver> screen_share_observers_;
   base::ObserverList<StatusAreaFocusObserver> status_area_focus_observers_;
   base::ObserverList<TracingObserver> tracing_observers_;
+  base::ObserverList<UpdateObserver> update_observers_;
   base::ObserverList<VirtualKeyboardObserver> virtual_keyboard_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(SystemTrayNotifier);