function contentLoaded(error, statusCode, headers, content)
    {
        if (error || !content || statusCode >= 400) {
            callback(null);
            return;
        }

        if (content.slice(0, 3) === ")]}")
            content = content.substring(content.indexOf('\n'));
        try {
            var payload = /** @type {!SourceMapV3} */ (JSON.parse(content));
            var baseURL = sourceMapURL.startsWith("data:") ? compiledURL : sourceMapURL;
            callback(new WebInspector.SourceMap(baseURL, payload));
        } catch(e) {
            console.error(e.message);
            callback(null);
        }
    }
@param {?Protocol.Error} error
@param {number} statusCode
@param {!NetworkAgent.Headers} headers
@param {string} content