Use user style sheets on Chromium

[mjethani]

Chromium now supports user style sheets via the cssOrigin option to tabs.insertCSS. Adblock Plus has already implemented changes to use the feature when it's available. uBlock Origin should do the same.

For reference, see Chromium bug #632009.

[gorhill]

Unfortunately, chrome.tabs.removeCSS is not implemented and this breaks some features in uBO, notably the toggling of cosmetic filtering (not a deal breaker, it just affects the real-time part of the feature), but more importantly this breaks the DOM inspector.

[uBlock-user]

It's a WIP apparently - https://bugs.chromium.org/p/chromium/issues/detail?id=608854

[gwarser]

Finally landed? https://chromium-review.googlesource.com/c/chromium/src/+/2250506

^{openstyles/stylus#248 (comment)}

[uBlock-user]

Yes, in Canary.

[gorhill]

I'm puzzled as to what motivated them to implement this now after all that time ignoring the original pull request.