Avoid cycle in Accessibility tree

This is a temporary fix. By ignoring the node when it is invisible, we
avoid navigating the cycle repeatedly. However the underlying issue
is not addressed, and requires further investigation.

Bug: 1020733
Change-Id: I70334259b4f271256f21dab47271f7a8346f1f7f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1919434
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#717755}

ui/views/accessibility/ax_window_obj_wrapper.cc

@@ -105,8 +105,12 @@ void AXWindowObjWrapper::Serialize(ui::AXNodeData* out_node_data) {
     out_node_data->role = ax::mojom::Role::kWindow;
   out_node_data->AddStringAttribute(ax::mojom::StringAttribute::kName,
                                     base::UTF16ToUTF8(window_->GetTitle()));
-  if (!window_->IsVisible())
+  if (!window_->IsVisible()) {
     out_node_data->AddState(ax::mojom::State::kInvisible);
+    // TODO(crbug/1020733): Find and address the root cause of the cycle, then
+    // remove the line below.
+    out_node_data->AddState(ax::mojom::State::kIgnored);
+  }
 
   out_node_data->relative_bounds.bounds =
       gfx::RectF(window_->GetBoundsInScreen());