This would be some follow up improvement work on the agl-shell-desktop. 

We currently lack some events to report errors back to the client. Not really sure if should adopt an async version of it, or if we should just stick with a sync version. Probably the latter easier to manage the modifications of all the applications. 

Another improvement is a dedicated object for passing which we can use to hang off surface properties (the roles and  additional parameters, like x, and y position, and the bounding box). 

Most likely we should correlate this with SPEC-3327 such that clients use that instead.