Refactor Chord vis (#5671)
Refactor Chord vis (#5671)

* refactor Chord vis

* Add PropTypes

* change module.exports to export default

airbnb/caravel,airbnb/caravel,airbnb/caravel,airbnb/superset,apache/incubator-superset,airbnb/superset,mistercrunch/panoramix,mistercrunch/panoramix,zhouyao1994/incubator-superset,apache/incubator-superset,zhouyao1994/incubator-superset,apache/incubator-superset,apache/incubator-superset,apache/incubator-superset,airbnb/caravel,zhouyao1994/incubator-superset,mistercrunch/panoramix,zhouyao1994/incubator-superset,airbnb/superset,zhouyao1994/incubator-superset,mistercrunch/panoramix,airbnb/superset