Depends on D138523
Given our current broadcast logic, we should not stumble on webextension contexts during broadcast.
This is because getAllBrowsingContextsInSubtree will not cross process boundaries.
Nevertheless, adding explicit support for WebExtensions in our filter method should be ok, with the added test.
Whenever we lift the JSWindowActor restrictions and rely on isBrowsingContextCompatible for filtering this will help avoid regressions.
Differential Revision: https://phabricator.services.mozilla.com/D138531
1aac6c54cd