Now that Stencil is core to all our parsing and caching flows for JS, we should directly use the JS::Stencil type from the dom::ScriptLoader and explicitly calling instantiate. This will allow us to build in-memory caches around JS::Stencil to improve our caching story.

It might be necessary to fix Bug 1687973 so that this proposed change can also cover the decode case. Even without that, it is still possible to support to do in-memory caching with just the non-decode path.

No one is actively working on this, so it is unlikely to land before the next release.