chromeos/test/data/network/wifi_proxy.onc

{
  "Name": "wifi1",
  "ProxySettings": {
    "Type": "Manual",
    "Manual": {
      "HTTPProxy" : {
        "Host" : "http.example.com",
        "Port" : 1234
      },
      "SecureHTTPProxy" : {
        "Host" : "https.example.com",
        "Port" : 3456
      },
      "FTPProxy" : {
        "Host" : "ftp.example.com",
        "Port" : 5678
      },
      "SOCKS" : {
        "Host" : "socks5://socks.example.com",
        "Port" : 7890
      }
    },
    "ExcludeDomains": [
      "google.com",
      "<local>"
    ]
  },
  "Type": "WiFi",
  "WiFi": {
    "Security": "None"
  }
}