Remove pre-2016 vendor-prefixed -webkit- CSS properties
Summary:
Per https://caniuse.com/ and MDN,
* `-webkit-border-radius` superseded by unprefixed `border-radius` supported since Chrome 5 released 05/2010, Safari 5 09/2010, Android Browser 2.2 05/2010
* `-webkit-box-shadow` superseded by unprefixed `box-shadow` supported since Chrome 10 released 03/2011, Safari 5.1 03/2012, Android Browser 4 10/2011
* `-webkit-box-sizing` superseded by unprefixed `box-sizing` supported since Chrome 10 released 03/2011, Safari 5.1 03/2012, Android Browser 4 10/2011
* `-webkit-transform` superseded by unprefixed `transform` supported since Chrome 36 released 07/2014, Safari 9 10/2015, Android Browser >4.4.4 >07/2014
* `-webkit-transition` superseded by unprefixed `transition` supported since Chrome 26 released 02/2013, Safari 9 10/2015, Android Browser 4.4 12/2013
Test Plan: None. Probably installing old browser versions if you don't trust documentation.
Reviewers: O1 Blessed Committers, valerio.bozzolan
Reviewed By: O1 Blessed Committers, valerio.bozzolan
Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Differential Revision: https://we.phorge.it/D25927
0470216497