Introducing this as a separate patch to simplify this changeset and first introduce a straightforward-ish implementation.
Differential Revision: https://phabricator.services.mozilla.com/D100731
Instead of having the web area be the implicit root, the search results should
exclusively be descendants of the target element that the search is called on.
Differential Revision: https://phabricator.services.mozilla.com/D91826
Eitan Isaacson
Morgan Reschenberg
Csoregi Natalia