Remove the -webkit-transition media feature (PrefixedTransitionMediaFeature)

Intent to Remove:
https://groups.google.com/a/chromium.org/d/msg/blink-dev/RO9K26CeuhI/ZWIx0Tb1LHgJ

BUG=335470

Review URL: https://codereview.chromium.org/135903006

git-svn-id: svn://svn.chromium.org/blink/trunk@165310 bbb929c8-8fbe-4397-9dbb-9b2b20218538