function prefixTransitionCallback(match, p1, p2) {
  if (p1 === 'var') return 'var';
  if (p1 === 'all') return 'all';
  if (p2 === 'all') return ', all';
  var prefixedValue = p1 ? supportedProperty(p1) : ", " + supportedProperty(p2);
  if (!prefixedValue) return p1 || p2;
  return prefixedValue;
}
Returns prefixed value transition/transform if needed.

@param {String} match
@param {String} p1
@param {String} p2
@return {String}
@api private