gistfile1.js

getMachineID = function () {
    var storedMacId = "";
    chrome.storage.local.get('machine-id', function (item) {
        storedMacId = item['machine-id'];
        console.log("tmp id = " + storedMacId)
        if (!storedMacId) {
            console.log("before get " + storedMacId)
            //storedMacId = getIdFromServer()
            storedMacId = guid();
            console.log("after get " + storedMacId)
            chrome.storage.local.set({'machine-id': storedMacId});
        }
        console.log("id = " + storedMacId)
        macId = storedMacId;
    });
    console.log("about to return "+storedMacId)
    return storedMacId;
}