1 files changed, 8 insertions, 28 deletions

diff --git a/application/palemoon/components/downloads/DownloadsCommon.jsm b/application/palemoon/components/downloads/DownloadsCommon.jsm
index 2bfd7b528..aac43d197 100644
--- a/application/palemoon/components/downloads/DownloadsCommon.jsm
+++ b/application/palemoon/components/downloads/DownloadsCommon.jsm
@@ -647,12 +647,8 @@ XPCOMUtils.defineLazyGetter(DownloadsCommon, "useJSTransfer", function () {
 function DownloadsDataCtor(aPrivate) {
   this._isPrivate = aPrivate;
 
-  // This Object contains all the available DownloadsDataItem objects, indexed by
-  // their globally unique identifier.  The identifiers of downloads that have
-  // been removed from the Download Manager data are still present, however the
-  // associated objects are replaced with the value "null".  This is required to
-  // prevent race conditions when populating the list asynchronously.
-  this.dataItems = {};
+  // Contains all the available DownloadsDataItem objects.
+  this.dataItems = new Set();
 
   // Array of view objects that should be notified when the available download
   // data changes.
@@ -690,8 +686,8 @@ DownloadsDataCtor.prototype = {
    */
   get canRemoveFinished()
   {
-    for (let [, dataItem] of Iterator(this.dataItems)) {
-      if (dataItem && !dataItem.inProgress) {
+    for (let dataItem of this.dataItems) {
+      if (!dataItem.inProgress) {
         return true;
       }
     }
@@ -716,7 +712,7 @@ DownloadsDataCtor.prototype = {
   {
     let dataItem = new DownloadsDataItem(aDownload);
     this._downloadToDataItemMap.set(aDownload, dataItem);
-    this.dataItems[dataItem.downloadGuid] = dataItem;
+    this.dataItems.add(dataItem);
 
     for (let view of this._views) {
       view.onDataItemAdded(dataItem, true);
@@ -745,7 +741,7 @@ DownloadsDataCtor.prototype = {
     }
 
     this._downloadToDataItemMap.delete(aDownload);
-    this.dataItems[dataItem.downloadGuid] = null;
+    this.dataItems.delete(dataItem);
     for (let view of this._views) {
       view.onDataItemRemoved(dataItem);
     }
@@ -861,14 +857,7 @@ DownloadsDataCtor.prototype = {
     //let loadedItemsArray = [dataItem
     //                        for each (dataItem in this.dataItems)
     //                        if (dataItem)];
-
-    let loadedItemsArray = [];
-
-    for each (let dataItem in this.dataItems) {
-      if (dataItem) {
-        loadedItemsArray.push(dataItem);
-      }
-    }
+    let loadedItemsArray = [...this.dataItems];
 
     loadedItemsArray.sort(function(a, b) b.download.startTime - a.download.startTime);
     loadedItemsArray.forEach(
@@ -1345,13 +1334,6 @@ function DownloadsDataItem(aSource)
 
 DownloadsDataItem.prototype = {
   /**
-   * The JavaScript API does not need identifiers for Download objects, so they
-   * are generated sequentially for the corresponding DownloadDataItem.
-   */
-  get _autoIncrementId() ++DownloadsDataItem.prototype.__lastId,
-  __lastId: 0,
-
-  /**
    * Initializes this object from the JavaScript API for downloads.
    *
    * The endTime property is initialized to the current date and time.
@@ -1362,8 +1344,6 @@ DownloadsDataItem.prototype = {
   _initFromJSDownload: function (aDownload)
   {
     this.download = aDownload;
-
-    this.downloadGuid = "id:" + this._autoIncrementId;
     this.endTime = Date.now();
 
     this.updateFromJSDownload();
@@ -2029,7 +2009,7 @@ DownloadsIndicatorDataCtor.prototype = {
   {
     let dataItems = this._isPrivate ? PrivateDownloadsData.dataItems
                                     : DownloadsData.dataItems;
-    for each (let dataItem in dataItems) {
+    for (let dataItem of dataItems) {
       if (dataItem && dataItem.inProgress) {
         yield dataItem;
       }