Fix the check to distinguish accessibility events.

ui/arc/notification/arc_custom_notification_view.cc

Index: ui/arc/notification/arc_custom_notification_view.cc
diff --git a/ui/arc/notification/arc_custom_notification_view.cc b/ui/arc/notification/arc_custom_notification_view.cc
index d640556c32c2f29ddc19f24d7f48010a9cb6f930..39c3c6e4337eb5797c2e18d6bbb02ad7862aee98 100644
--- a/ui/arc/notification/arc_custom_notification_view.cc
+++ b/ui/arc/notification/arc_custom_notification_view.cc
@@ -553,9 +553,12 @@ bool ArcCustomNotificationView::OnMousePressed(const ui::MouseEvent& event) {
   // All mouse clicks or touches should be sent to corresponding Android view
   // because the surface is on this view, so receiving a mouse pressed event
   // means the event is generated by automation API.
+  // We can distinguish events from automation API by checking the target of the
+  // event because the target of all events generated by automation API is set
+  // to nullptr.
   if (event.IsOnlyLeftMouseButton() &&
       item_->expand_state() != mojom::ArcNotificationExpandState::FIXED_SIZE &&
-      event.target() != surface_->window()) {
+      event.target() == nullptr) {
     item_->ToggleExpansion();
     return true;
   }