function scriptSourceLoaded(scriptNumber, scriptSource)
    {
        sources[scriptNumber] = scriptSource || "";
        // Eval scripts as fast as possible.
        while (typeof sources[scriptToEval] !== "undefined") {
            evaluateScript(urls[scriptToEval], sources[scriptToEval]);
            ++scriptToEval;
        }
    }
@param {number} scriptNumber
@param {string=} scriptSource