Do not hide the web notification popups by the system tray, rather let them avoid (2nd)

ash/system/tray/system_tray.h

Index: ash/system/tray/system_tray.h
diff --git a/ash/system/tray/system_tray.h b/ash/system/tray/system_tray.h
index 322c65240c6f14129d1cd5f0f9b3c9e37a621b40..ded64750026dcce4f15b24e9a23c4c3413e76223 100644
--- a/ash/system/tray/system_tray.h
+++ b/ash/system/tray/system_tray.h
@@ -191,6 +191,10 @@ class ASH_EXPORT SystemTray : public internal::TrayBackgroundView,
   // |notification_items_|, or destroys it if there are no notification items.
   void UpdateNotificationBubble();
 
+  // Checks the current status of the system tray and updates the web
+  // notification tray according to the current status.
+  void UpdateWebNotifications();
+
   const ScopedVector<SystemTrayItem>& items() const { return items_; }
 
   // Overridden from internal::ActionableView.