Summary:
Ref T4103. This is just incremental cleanup:
- Add "internal" settings, which aren't editable via the UI. They can still do validation and run through the normal pathway. Move a couple settings to use this.
- Remove `getPreference()` on `PhabricatorUser`, which was a sort of prototype version of `getUserSetting()`.
- Make `getUserSetting()` validate setting values before returning them, to improve robustness if we change allowable values later.
- Add a user setting cache, since reading user settings was getting fairly expensive on Calendar.
- Improve performance of setting validation for timezone setting (don't require building/computing all timezone offsets).
- Since we have the cache anyway, make the timezone override a little more general in its approach.
- Move editor stuff to use `getUserSetting()`.
Test Plan:
- Changed search scopes.
- Reconciled local and server timezone settings by ignoring and changing timezones.
- Changed date/time settings, browsed Calendar, queried date ranges.
- Verified editor links generate properly in Diffusion.
- Browsed around with time/date settings looking at timestamps.
- Grepped for `getPreference()`, nuked all the ones coming off `$user` or `$viewer` that I could find.
- Changed accessiblity to high-contrast colors.
- Ran all unit tests.
- Grepped for removed constants.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T4103
Differential Revision: https://secure.phabricator.com/D16015
67482fd19d