Once bug 1692468 is fixed web elements from WebDriver classic could be also shared by WebDriver BiDi. To get this implemented we have to follow the BiDi specification around serialization of platform objects of type node:

https://w3c.github.io/webdriver-bidi/#ref-for-boundary-point-node

The following restrictions will apply to this bug so that we can better split the work into several bugs:

1. Start with the object itself and do not care about child nodes (maxDepth argument)
2. Do not add support for node details (will be done by bug 1770733)
3. Support the sharedId property

I've started the work on this bug today and got existing serialization tests to pass. As noticed there is no notion of a node details flag anymore in the BiDi spec. As such there is no such basic support anymore, and I'm going ahead and will implement the complete serialization.

Note that sharing elements and shadow roots between Marionette and WebDriver BiDi will be done via bug 1770733. For now clients can request ownership and get a handle included to reference back the remote value.

(In reply to Henrik Skupin (:whimboo) [⌚️UTC+2] from comment #1)

Note that sharing elements and shadow roots between Marionette and WebDriver BiDi will be done via bug 1770733. For now clients can request ownership and get a handle included to reference back the remote value.

Because of that this bug is no longer blocked on bug 1692468.

Right now we actually do not differentiate between platform objects of type Node and Element specifically.

I filed bug 1802137 which moves out the serialization of Shadow DOM related scenarios.

Depends on D163004

https://hg.mozilla.org/mozilla-central/rev/4d7899fd983b
https://hg.mozilla.org/mozilla-central/rev/17958bffdfcf