Another issue that the tricky "seem" to fix is that we need to expose things outside the namespace of your extension name (window.screen). You can set "extra entry points" for those, that will ensure the extension will be loaded correctly when accessed. So you will probably mark all the properties you set as "entry-points".

We have tests and examples of how these entry points features work.

BUT, why isn't the extension name "screen" instead of "xwalk.screen"?