Reading that bug, it sounds like it was fixed in https://chromium.googlesource.com/chromium/src/+/51cd319fd6a... and the bug status is just incorrect?
That web requests in PDF content types are not subject to the same approach as web requests in HTML content types is the problem. Disabling all JS is a blunt instrument akin to telling someone that being able to disable JS for other webpages is as good as more nuanced ad block extension.
No, sorry if I was unclear. What I'm in favor of is my extensions being able to handle/filter web requests on PDFs the same as they do for webpages, irrespective of JS settings. JS is only under discussion here because of the linked commit and I'm saying that's not good enough.
edit to clarify: sorry I thought you thought that fix was trying to fix the bug, but you weren't, so this comment doesn't make much sense.