After PR 8394, where the l10n service was converted to be asynchronous, we're no longer calling `_adjustWidth` after updating the `findMsg` label. Hence it's currently possible that the width of the findbar won't be correct. The solution is simple though, just call `_adjustWidth` after the `findMsg` label has been (asynchronously) updated.
Another existing issue, which was an oversight in PR 8132, is that `PDFFindBar.updateResultsCount` may be called directly from `PDFFindController`. In that case, we're not calling `_adjustWidth` at all, which means that the findbar may also not have the correct width.
The simple solution here is to always call `_adjustWidth` at the end of `updateResultsCount` (which is why we no longer need the `_adjustWidth` call at the end of `updateUIState`).
Currently we're *only* hiding the label, but not actually resetting it until a new match is found.
Obviously it's being hidden, but it seems that it really ought to be completely reset as well (since e.g. `PDFFindBar.reset` won't technically reset *all* state otherwise).
Note that these files were among the first to be converted to ES6 classes, so it probably makes sense to do another pass to bring them inline with the most recent ES6 conversions.
Moreover, rename `FindStates` to `FindState` since enumeration names are
usually not in plural, for readability and consistency with the ones in
`src/shared/util.js`.
Note that as discussed on IRC, this makes the viewer slightly slower to load *only* in `gulp server` mode, however the difference seem slight enough that I think it will be fine.
