This is an issue where in jQuery v3 the result of outerHeight on a node
that doesn’t exist is now “undefined” rather than “null”, which means
it will no longer cast to a Number but rather NaN. For this, we create
the safeOuterHeight and safeOuterWidth functions to safely return a
result (or 0).
This is a better solution than manually going to each instance and
ORing it with 0 for type safety.
https://stackoverflow.com/questions/41454285/jquery-outerheight-returns-
undefined-instead-of-null
- Remove `perfect-scrollbar` from `static/third` and fetch it from npm.
- Upgrade `perfect-scrollbar` to 0.7.1.
- Bump up the `PROVISION_VERSION` to 5.6.
Changed `wheelSpeed` in "static/js/scroll_bar.js" to 0.5, because when it
20, the scrollbar scrolls very fast.
Changed 'wheelSpeed' in "static/js/emoji_picker.js" from 25 to 0.68
(based on tabbott's testing of scrolling through the emoji list).
Part of #1709.