Name already in use

…1200)

* Split attachShadow element list into separate definition so it can be referenced from EditContext spec

* Stray newline

* Change to `valid shadow host name`

Co-authored-by: Anne van Kesteren <annevk@annevk.nl>

* Update name in other location

* Export the new `<dfn>`.

Co-authored-by: Anne van Kesteren <annevk@annevk.nl>

* nits

---------

Co-authored-by: Anne van Kesteren <annevk@annevk.nl>

- This implements an optimization that puts all children on
  non-dependent signals (i.e., those associated with a controller).
  This allows "intermediate" nodes (e.g., B in A follows B follows C)
  to be garbage collected if they are being kept alive to propagate
  aborts.

- This removes the follow algorithm, so callsites will need to be
  updated.

- The "create a composite abort signal" algorithm takes an interface so
  that TaskSignal.any() can easily hook into it, but create a 
  TaskSignal.

- Some algorithms that invoke "follow" create an AbortSignal in a 
  particular realm. This enables doing that, but borrows some language 
  from elsewhere in the spec w.r.t. doing the default thing. Neither of
  the other two static members specify a realm.

Follow-up PRs:

- whatwg/fetch#1646
- w3c/ServiceWorker#1678
- whatwg/streams#1277

This also sets the stage to make AbortSignal's "signal abort" fully 
internal. #1194 tracks the remainder.

Tests: web-platform-tests/wpt#37434 and web-platform-tests/wpt#39785.

Fixes #920.

Fixes #1178.

For w3c/ServiceWorker#1674.

For w3c/ServiceWorker#1674.

Also always include for=tree for ancestors, descendants, and parents.

Tests: web-platform-tests/wpt#38636.

Fixes #857.

Stop exporting it as per discussion in whatwg/html#8575.

The existing design had some leaks and was also different from implementations. In particular, assume you have two mutation observers and a change triggered the first one as well as a slot change. Then if in the reaction to the first one a further change triggers the second one it would run before the slot change per the existing specification, but that didn't match implementations and more importantly didn't allow for garbage collection.

Test: https://github.com/web-platform-tests/wpt/blob/master/shadow-dom/slotchange-event.html#L540-L594.

Fixes #713. Fixes #1159. Closes #720.

Closes #1149.

Marked as "Editorial" due to minor wording tweaks here and there.

And improve the algorithm "headers" at the same time by listing the argument types and default values.

Fixes #1134.

Also correct createContextualFragment() link.

Fixes #1130.

See https://github.com/whatwg/spec-factory for details.

Following discussions in whatwg/html#8340, the events index in the HTML spec will be restricted to event types that gets fired within the HTML spec. The slotchange event will be dropped as a result.

…t/touchmove events

Tests: web-platform-tests/wpt#34623

Fixes #365.

annevk said "that's not great" out loud. Twice!

Fixes #1065.

Worklets are designed with minimal event loops such that they need only run a single task and corresponding microtasks, making APIs that schedule additional tasks unsuitable for worklets. As such, we restrict the availability of AbortSignal.timeout to Window and Worker since the API schedules a task to implement the timeout.

Closes #1054.

Closes #951.

See tc39/proposal-shadowrealm#331 for context.

Tests: web-platform-tests/wpt#31852.

See https://github.com/whatwg/spec-factory for details.

Tests: web-platform-tests/wpt#31947.

Closes #927.

Also clean up some remaining instances that didn't use signal.reason.

Closes #961.

Closes #1036.

See whatwg/streams#1165 (comment) for additional context.

Tests: #1027.

Co-authored-by: Anne van Kesteren <annevk@annevk.nl>