Chrome auto-login extension does not bypass basic authentication when added via selenium

Question

I have some code which initializes a selenium webdriver and opens a chrome page to my router. The router requires basic http authentication which selenium doesn't support. I have managed to discover a way to bypass this authentication with the use of a chrome extension (see below)

background.js

function callbackFn(details) {
return {
    authCredentials: {
        username: "user",
        password: "pass"
    }
};

}

chrome.webRequest.onAuthRequired.addListener(
        callbackFn,
        {urls: ["<all_urls>"]},
        ['blocking']
);

manifest.json

{
    "version": "1.0.0",
    "manifest_version": 2,
    "name": "Chrome Auto Login",
    "permissions": [
        "proxy",
        "tabs",
        "unlimitedStorage",
        "storage",
        "<all_urls>",
        "webRequest",
        "webRequestBlocking"
    ],
    "background": {
        "scripts": ["background.js"]
    },
    "minimum_chrome_version":"22.0.0"
}

To verify this functionality I enable the above extension in chrome. I go to my router page with the authentication and it completely bypasses the screen. Which is great as I no longer need selenium to handle this login process.

However, once I add the extension via selenium, I get entirely different results and the code doesn't work the same in automated chrome, as it does in standard chrome.

    private class ChromeOptionsEx : ChromeOptions
    {
        public override ICapabilities ToCapabilities()
        {
            var r = (DesiredCapabilities)base.ToCapabilities();
            r.SetCapability("pageLoadStrategy", "none");

            AddExtension(@"ChromeAutoLoginExt.crx");
            return r;
        }
    }


ChromeOptionsEx opt = new ChromeOptionsEx();
m_Driver = new ChromeDriver(opt);

//extension appears but does not bypass router login
    m_Driver.Navigate().GoToUrl("chrome://extensions");

The extension appears and its enabled when I launch chrome via selenium but it does not have the same desired results.

Can anyone help?