Casting Xfinity Stream Content to Chromecast Now Available
Good news! Xfinity customers can now cast programming from the Xfinity Stream app directly to Chromecast devices and supported-TVs. Just look for the casting icon on the top righthand side of the screen to start casting.
Visit here for more info: https://www.xfinity.com/support/articles/cast-xfinity-stream-to-chromecast.