d.  * @param {boolean=} opt_userInitiated If the load is a result of a user action.  * @return {Object.<!goog.async.Deferred>} A mapping from id (String) to  *     deferred objects that will callback or errback when the load for that  *     id is finished.  * @private  */ goog.module.ModuleManager.prototype.loadModulesOrEnqueue