AM/PM string, warning message, and position of hour/minute/ampm should display correctly based on users' locale.
This should come from Intl.getDisplayNames
As per the latest planning together with PM and the team, we're not going to have time picker UI. Bug 1315911 had landed on pref-off the pop-up.
:wesley_huang - I understand the repriotization, but why does it result in resolved/wontfix?
Likely in the short term we're not going to spend efforts on the time picker UI. But it's ok to leave it open (for future tracking purpose) so I'm making it reopened.