fix Gid not exists

app/download.service.ts

@@ -153,7 +153,9 @@ export class DownloadService {
                             gids!.map((value, index, array) => {
                                 let s = this.downloadList.get(value);
                                 if (!s) {
-                                    throw 'Gid not exists';
+                                    // in refreshDownloadList, a job may disappear between tellActive and tellWaiting
+                                    console.warn('Gid not exists ' + value);
+                                    return new DownloadStatus();
                                 }
                                 return s;
                             })
@@ -207,14 +209,6 @@ export class DownloadService {
         return taskId;
     }
 
-    async addUri (url: string, destination: string): Promise<string> {
-        await this.open;
-        let taskId = this.createId();
-        let gid = await this.aria2.addUri([url], {dir: destination});
-        this.taskMap.set(taskId, [gid]);
-        return taskId;
-    }
-
     async pause (id: string): Promise<void> {
         await this.open;
         try {