As discussed in https://bugzilla.mozilla.org/show_bug.cgi?id=1213450#c49 and beyond, Chrome does not replace dashes `-` with underscores `_` in the return value of getAcceptLanguages() so we should also not do that replacement.

Review commit: https://reviewboard.mozilla.org/r/36643/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/36643/

Comment on attachment 8723634 [details] MozReview Request: Bug 1251289 - Fix chrome.i18n.getAcceptLanguages to *not* replace dashes with underscores in language codes, r?kmag https://reviewboard.mozilla.org/r/36643/#review33163 Thanks! ::: toolkit/components/extensions/ExtensionUtils.jsm:439 (Diff revision 1) > }); `result.trim().split(/\s*,\s*/g)` would be simpler.

Comment on attachment 8723634 [details] MozReview Request: Bug 1251289 - Fix chrome.i18n.getAcceptLanguages to *not* replace dashes with underscores in language codes, r?kmag Review request updated; see interdiff: https://reviewboard.mozilla.org/r/36643/diff/1-2/

https://reviewboard.mozilla.org/r/36643/#review33163 > `result.trim().split(/\s*,\s*/g)` would be simpler. Nice. :) I don't think I need that initial `trim()` anymore though, do I. I wrote it without it and it seems to return what I want.