ColumnChartMediaInfo

// Create a new ColumnChart to display within the PopupTemplate
// Create the ChartMediaInfoValue
let columnChartValue = new ChartMediaInfoValue({
  colors: [[220, 123, 4, 1], [229, 80, 53, 1], ...],
  fields: ["<array of strings indicating fields>"],
  normalizeField: null,
  tooltipField: "<field name>"
});

// Create the ColumnChartMediaInfo media type
let columnChart = new ColumnChartMediaInfo({
  title: "<b>Count by type</b>",
  caption: "Per block",
  value: columnChartValue
});

// Create the MediaContent
let mediaElement = new MediaContent({
  mediaInfos: [columnChart]
});