Provide clients with a process to add their own Snippets

Background

Due to the snippet library and related API changes in the 0.6.0 release of the web ext SDK, AdBlock can no longer add an additional Snippet to the snippet library.

Use case

AdBlock created it's own isolated snippet when the Distraction Control filter lists were added a couple of years ago. The specificClicker snippet was added because there wasn't a snippet that would click an element on a page. The specificClicker snippet clicks element(s) in the document if / when all of the element(s) are found. The elements on the page can be identified with either a CSS selector or an XPath expression.

Previously, AdBlock could update the Snippet library at runtime, adding the specificClicker snippet if necessary.

The module for the specificClicker can be found here.

What to change

I believe there are two options available to us

• allow web ext clients to add snippets (in this case, an isolated snippet) either at build or runtime
• add the specificClicker snippet to the eyeo snippet library

Additionally, I would like to minimize any changes to the Distraction Control filter list.