Fix - download progress resets to zero momentarily on download items when a new download begins

- Downloads window displays "0%" in the title bar progress briefly after a download completes.

toolkit/components/downloads/src/nsDownloadManager.cpp

@@ -529,6 +529,13 @@ nsDownloadManager::AddDownload(DownloadType aDownloadType,
   nsCOMPtr<nsIRDFResource> downloadRes;
   gRDFService->GetUnicodeResource(path, getter_AddRefs(downloadRes));
 
+  // Save state of existing downloads NOW... because inserting the new 
+  // download resource into the container will cause the FE to rebuild and all 
+  // the active downloads will have their progress reset (since progress is held
+  // mostly by the FE and not the datasource) until they get another progress
+  // notification (which could be a while for slow downloads).
+  SaveState();
+
   // if the resource is in the container already (the user has already
   // downloaded this file), remove it
   PRInt32 itemIndex;

toolkit/mozapps/downloads/content/downloads.js

@@ -407,6 +407,7 @@ function onUpdateProgress()
   var numActiveDownloads = gActiveDownloads.length;
   if (numActiveDownloads == 0) {
     window.title = document.documentElement.getAttribute("statictitle");
+    gLastComputedMean = 0;
     return;
   }
     
@@ -419,6 +420,15 @@ function onUpdateProgress()
   }
 
   mean = Math.round(mean / numActiveDownloads);
+  
+  // At the end of a download, progress is set from 100% to 0% for 
+  // some reason. We can identify this case because at this point the
+  // mean progress will be zero but the last computed mean will be
+  // greater than zero. 
+  if (mean == 0 && gLastComputedMean > 0) {
+    window.title = document.documentElement.getAttribute("statictitle");
+    return;
+  }
   if (mean != gLastComputedMean) {
     gLastComputedMean = mean;
     var strings = document.getElementById("downloadStrings");