We'll want to use UTF-8 when we switch to using ICU4x because Rust is all UTF-8. We
can switch the external facing APIs now, and update the internal implementations
later.
Differential Revision: https://phabricator.services.mozilla.com/D94850
Introduce a separate API for retrieving locale set from the host environment
used for regional preferences localization.
MozReview-Commit-ID: 3597QstZjS3
--HG--
extra : rebase_source : 2ac30ba2f2c9bd1ed308cfe7be88f6add4f0f5ae