[w3c/webcomponents] Fix #556, make focus navigation work when shadow host's tabindex is -1 (#557)

The Shadow DOM spec section 6.3 (sequential focus navigation) unintentionally excluded all shadow hosts with nagative tabindex in Step 3.1.3. This was unexpected for shadow hosts with `delagatesFocus=false` shadow root.

Before:
 - Exclude all shadow hosts with tabindex < 0

After:
 - Allow shadow hosts with tabindex < 0, but only when `delegatesFocus=false`
 - In sorting by tabindex, treat such shadow hosts as `tabindex=0`
 - Exclude those shadow hosts in Step 4.



You can view, comment on, or merge this pull request online at:

  https://github.com/w3c/webcomponents/pull/557

-- Commit Summary --

  * Fix #556, make focus navigation work when shadow host's tabindex is -1

-- File Changes --

    M spec/shadow/index.html (14)

-- Patch Links --

https://github.com/w3c/webcomponents/pull/557.patch
https://github.com/w3c/webcomponents/pull/557.diff

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/w3c/webcomponents/pull/557