ash: Remove broken display notification suppression when settings is open

ash/system/chromeos/screen_layout_observer.h

Index: ash/system/chromeos/screen_layout_observer.h
diff --git a/ash/system/chromeos/screen_layout_observer.h b/ash/system/chromeos/screen_layout_observer.h
index 59409c66190944c9da3d7bc1c8d5c8440dfd5b26..bdea83456513619286c066463c4671afd5665ce6 100644
--- a/ash/system/chromeos/screen_layout_observer.h
+++ b/ash/system/chromeos/screen_layout_observer.h
@@ -29,6 +29,12 @@ class ASH_EXPORT ScreenLayoutObserver : public WmDisplayObserver {
   // Overridden from WmDisplayObserver:
   void OnDisplayConfigurationChanged() override;
 
+  // Notifications are shown in production and are not shown in unit tests.
+  // Allow individual unit tests to show notifications.
+  void set_show_notifications_for_testing(bool show) {
+    show_notifications_for_testing = show;
+  }
+
  private:
   friend class ScreenLayoutObserverTest;
 
@@ -56,6 +62,8 @@ class ASH_EXPORT ScreenLayoutObserver : public WmDisplayObserver {
 
   DisplayInfoMap display_info_;
 
+  bool show_notifications_for_testing = true;
+
   DISALLOW_COPY_AND_ASSIGN(ScreenLayoutObserver);
 };