UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.33 Safari/537.36

Steps to reproduce the problem:
This was briefly mentioned in a previous issue: https://bugs.chromium.org/p/chromium/issues/detail?id=79734#c9

What is the expected behavior?
Despite, SharedWorkers potentially being used by multiple documents, it is essential, for any extension that is interested in them, to associate them with the document which first caused the SharedWorker to be created; be it for developer tools that want to show SharedWorkers created by a particular page, or ad blocking extensions that want to block them (or any of their subrequest) but only on particular pages. 

What went wrong?
SharedWorkers do not have any information about the document which caused them to be created

WebStore page: 

Did this work before? No 

Chrome version: 58.0.3029.33  Channel: beta
OS Version: OS X 10.12.3
Flash Version: Shockwave Flash 25.0 r0

For reference, as opposed to the webRequest API currently, the child-src CSP policy handles SharedWorkers as if they were associated with the document that they have been created for.