Android Chrome wifi “Sign into Wi-Fi network” how to disable redirect to www.Google.com
As I answered here, if you're rooted,


  Just execute su then settings put global captive_portal_server SERVER_YOU_WANT_TO_USE in a terminal emulator app or ADB shell.


However, not all servers respond properly to HTTP 204 requests, so CNN might not be feasible for example. A possible list of usable ones can be seen in this answer.