0312 增加下载事件通知，增加支付回调地址

hch

2019-09-10 f7ecc97bcc0e95bd6bd05526a280901a6957b4e3

 System/AssetVersion/DownLoadWin.cs

@@ -50,11 +50,13 @@
        protected override void OnAfterOpen()

        {

            DownLoadAndDiscompressTask.Instance.downLoadStepChangeEvent += OnDownLoadStepChange;

            SDKUtility.Instance.DownloadStart();

        }



        protected override void OnPreClose()

        {

            DownLoadAndDiscompressTask.Instance.downLoadStepChangeEvent -= OnDownLoadStepChange;

            SDKUtility.Instance.DownloadEnd();

        }



        protected override void OnAfterClose()