Once our "native" webkit emulation is ready to ship (via bug 1259345), we should get rid of CSSUnprefixingService.js and related code (basically everything that was added in bug 1107378). (As noted in bug 1259345 comment 1, we should also make sure that the CSSUnprefixingService is no longer needed before we do this, i.e. that our native support is at least as good as our hacky JS-and-domain-whitelist support was. Assuming that this is the case, good riddance to the hacky JS-and-domain-whitelist code!)

Our "native" webkit unprefixing implementation (which *suppresses* CSSUnprefixingService[1]) seems to have stuck -- it shipped in 49, and now we're two releases later, shipping 51. So let's do this removal of CSSUnprefixingService, since it's been replaced with something better & it's effectively dead code. [1] For the record, the suppression happens via this early-return in ShouldUseUnprefixingService(): https://dxr.mozilla.org/mozilla-central/rev/1d025ac534a6333a8170a59a95a8a3673d4028ee/layout/style/nsCSSParser.cpp#7201-7202,7208-7211 (I'm just noting that since it adds extra confidence that we can rip out this code without affecting anything.)

+1, was just thinking about this bug yesterday!

Comment on attachment 8833529 [details] Bug 1259348 part 1: Remove CSSUnprefixingService.js and associated code (since it's been supplanted by built-in webkit-prefixed-CSS support). https://reviewboard.mozilla.org/r/109722/#review110828

Comment on attachment 8833530 [details] Bug 1259348 part 2: Simplify logic in CSSParserImpl::LookupKeywordPrefixAware. https://reviewboard.mozilla.org/r/109724/#review110830

Pushed by dholbert@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/171262d16e80 part 1: Remove CSSUnprefixingService.js and associated code (since it's been supplanted by built-in webkit-prefixed-CSS support). r=mats https://hg.mozilla.org/integration/autoland/rev/05b672699c45 part 2: Simplify logic in CSSParserImpl::LookupKeywordPrefixAware. r=mats

https://hg.mozilla.org/mozilla-central/rev/171262d16e80 https://hg.mozilla.org/mozilla-central/rev/05b672699c45