mash: Fix system tray bubble not closing for clicks outside its bounds

services/ui/public/cpp/window_tree_client.h

Index: services/ui/public/cpp/window_tree_client.h
diff --git a/services/ui/public/cpp/window_tree_client.h b/services/ui/public/cpp/window_tree_client.h
index 5f11f731b219761bb7f976d573e59a5f24b07486..814eea7d308c5fdf0f0ea2cb0ce77954254ad61d 100644
--- a/services/ui/public/cpp/window_tree_client.h
+++ b/services/ui/public/cpp/window_tree_client.h
@@ -264,6 +264,10 @@ class WindowTreeClient : public mojom::WindowTreeClient,
   // Callback passed from WmPerformMoveLoop().
   void OnWmMoveLoopCompleted(uint32_t change_id, bool completed);
 
+  // Notifies the delegate of an |event| matching an event observer. |target|
+  // may be null if the event did not hit a window owned by this client.
+  void SendToEventObserver(const ui::Event& event, Window* target);
+
   // Overridden from WindowTreeClient:
   void OnEmbed(ClientSpecificId client_id,
                mojom::WindowDataPtr root,