chromeos/test/data/network/policy/policy_wifi1_update.onc

{
  "NetworkConfigurations": [
    {
      "GUID": "policy_wifi1",
      "Type": "WiFi",
      "Name": "Managed wifi1",
      "WiFi": {
        "Passphrase": "another passphrase",
        "Recommended": [ "AutoConnect", "Passphrase" ],
        "SSID": "wifi1",
        "Security": "WPA-PSK"
      }
    }
  ],
  "Type": "UnencryptedConfiguration"
}