Endpoint for sequential focus navigation

[foolip]

This is a clone of whatwg/html#4151, since this could be defined either in WebDriver or in HTML.

The bit that requires a WebDriver endpoint:
https://html.spec.whatwg.org/multipage/interaction.html#sequential-focus-navigation

The algorithm starting with "When the user requests that focus move" is typically invoked by pressing the TAB key, but this may not be universally true. Having a WebDriver API for this would make it possible to trigger focus navigation without making such assumptions.

Straw proposal: An endpoint /session/{session id}/focus to which one would POST { "direction": "forward" } or { "direction": "backward" }.

This would help resolve web-platform-tests/wpt#13379, although it is not the only way it could be resolved.

[christian-bromann]

@foolip this action can technically also be triggered with the actions command, no?

[foolip]

@christian-bromann do you mean by sending TAB or Shift-TAB input? That is indeed what was done in https://github.com/web-platform-tests/wpt/pull/17523/files#diff-6d8e45f94b9f120a854ec188b4857275R67 and it presumably work, but the question is if it works on all browsers. Although I can't find the discussion now, I'm pretty sure @jgraham raised this doubt.