Feature request: Support for Document.createTreeWalker

I want to create dom tree walker inside my worker script but it's not supported yet. Any plans to support it in near future?

Start by locating the worker script's Document API implementation and checking how Document.createTreeWalker is currently handled. Confirm the expected worker-side behavior and identify the relevant tests before defining what support would mean; done should be demonstrated by passing coverage for creating and using a tree walker.

Written by the indexing model from the issue text.