function handleAbortRequestComplete(id, xhr, isError) {
        var domParser = new DOMParser(),
            responseDoc = domParser.parseFromString(xhr.responseText, "application/xml"),
            errorEls = responseDoc.getElementsByTagName("Error"),
            awsErrorMsg;

        options.log(qq.format("Abort response status {}, body = {}", xhr.status, xhr.responseText));

        // If the base requester has determine this a failure, give up.
        if (isError) {
            options.log(qq.format("Abort Multipart Upload request for {} failed with status {}.", id, xhr.status), "error");
        }
        else {
            // Make sure the correct bucket and key has been specified in the XML response from AWS.
            if (errorEls.length) {
                isError = true;
                awsErrorMsg = responseDoc.getElementsByTagName("Message")[0].textContent;
                options.log(qq.format("Failed to Abort Multipart Upload request for {}.  Error: {}", id, awsErrorMsg), "error");
            }
            else {
                options.log(qq.format("Abort MPU request succeeded for file ID {}.", id));
            }
        }
    }
Called by the base ajax requester when the response has been received.  We definitively determine here if the
"Abort MPU" request has been a success or not.

@param id ID associated with the file.
@param xhr `XMLHttpRequest` object containing the response, among other things.
@param isError A boolean indicating success or failure according to the base ajax requester (primarily based on status code).