https://csswizardry.com/demos/2018/11/import/blocked-by-css.html OR https://csswizardry.com/demos/2018/11/import/blocked-by-js.html
**Steps to reproduce the problem:**
1. Have a page with a synchronous `<link rel="stylesheet" />` and/or synchronous `<script src="">` BEFORE an in-page `@import url(style.css)` that omits the optional quote marks.
2. Reload page with Network panel open
3. Note lack of parallelisation: files are serialised
4. Edit `@import url(style.css)` to be `@import url("style.css")` (note addition of quote marks)
5. Refresh and observe waterfall
**What is the expected behaviour?**
I would expect the Preload Scanner to identify the IMPORT regardless of the presence of quote marks
**What went wrong?**
The Preload Scanner isn’t noticing @import URLs that omit OPTIONAL quotes
I'm currently fixing a similar (identical?) issue in Chromium's CSSPreloadScanner. Patch is up at https://chromium-review.googlesource.com/c/chromium/src/+/1331042/3
At the very least, the tests can be reused here.