Tests Input.dragIntercepted event.
{
  "items": [
    {
      "mimeType": "text/uri-list",
      "data": "https://example.com/",
      "title": "Drag Me!"
    },
    {
      "mimeType": "text/plain",
      "data": "https://example.com/"
    },
    {
      "mimeType": "text/html",
      "data": "<a href=\"https://example.com/\">Drag Me!</a>",
      "baseURL": "https://example.com/"
    }
  ],
  "dragOperationsMask": -1
}