close #289, don't listen onDeterminingFilename event

The issue of browser "save as" takes too long is persist when listen onDeterminingFilename event. It seems like the browser won't remove the listener on the event after profile closed. Need more investigation on this one.

Author: leoding86

src/background/services/DownloadService.js

@@ -24,7 +24,7 @@ class DownloadService extends AbstractService {
 
   constructor() {
     super();
-    this.listenOnDeterminingFilename();
+    // this.listenOnDeterminingFilename();
   }
 
   listenOnDeterminingFilename() {
@@ -131,7 +131,7 @@ class DownloadService extends AbstractService {
   }
 
   async saveFile({ url, filename }) {
-    this.cacheDownloadIdFilename(url, filename);
+    // this.cacheDownloadIdFilename(url, filename);
     const downloadId = await FileSystem.getDefault().saveFile({ url, filename });
     return downloadId;
   }