--- a/browser/components/downloads/src/DownloadsUI.js
+++ b/browser/components/downloads/src/DownloadsUI.js
@@ -55,45 +55,45 @@ DownloadsUI.prototype = {
   //////////////////////////////////////////////////////////////////////////////
   //// nsISupports
 
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIDownloadManagerUI]),
 
   //////////////////////////////////////////////////////////////////////////////
   //// nsIDownloadManagerUI
 
-  show: function DUI_show(aWindowContext, aID, aReason, aUsePrivateUI)
+  show: function DUI_show(aWindowContext, aDownload, aReason, aUsePrivateUI)
   {
     if (DownloadsCommon.useToolkitUI) {
-      this._toolkitUI.show(aWindowContext, aID, aReason, aUsePrivateUI);
+      this._toolkitUI.show(aWindowContext, aDownload, aReason, aUsePrivateUI);
       return;
     }
 
     if (!aReason) {
       aReason = Ci.nsIDownloadManagerUI.REASON_USER_INTERACTED;
     }
 
     if (aReason == Ci.nsIDownloadManagerUI.REASON_NEW_DOWNLOAD) {
       const kMinimized = Ci.nsIDOMChromeWindow.STATE_MINIMIZED;
       let browserWin = gBrowserGlue.getMostRecentBrowserWindow();
 
       if (!browserWin || browserWin.windowState == kMinimized) {
-        this._showDownloadManagerUI(aWindowContext, aID, aReason, aUsePrivateUI);
+        this._showDownloadManagerUI(aWindowContext, aUsePrivateUI);
       }
       else {
         // If the indicator is visible, then new download notifications are
         // already handled by the panel service.
         browserWin.DownloadsButton.checkIsVisible(function(isVisible) {
           if (!isVisible) {
-            this._showDownloadManagerUI(aWindowContext, aID, aReason, aUsePrivateUI);
+            this._showDownloadManagerUI(aWindowContext, aUsePrivateUI);
           }
         }.bind(this));
       }
     } else {
-      this._showDownloadManagerUI(aWindowContext, aID, aReason, aUsePrivateUI);
+      this._showDownloadManagerUI(aWindowContext, aUsePrivateUI);
     }
   },
 
   get visible()
   {
     // If we're still using the toolkit downloads manager, delegate the call
     // to it. Otherwise, return true for now, until we decide on how we want
     // to indicate that a new download has started if a browser window is
@@ -107,17 +107,17 @@ DownloadsUI.prototype = {
       this._toolkitUI.getAttention();
     }
   },
 
   /**
    * Helper function that opens the download manager UI.
    */
   _showDownloadManagerUI:
-  function DUI_showDownloadManagerUI(aWindowContext, aID, aReason, aUsePrivateUI)
+  function DUI_showDownloadManagerUI(aWindowContext, aUsePrivateUI)
   {
     // If we weren't given a window context, try to find a browser window
     // to use as our parent - and if that doesn't work, error out and give up.
     let parentWindow = aWindowContext;
     if (!parentWindow) {
       parentWindow = RecentWindow.getMostRecentBrowserWindow({ private: !!aUsePrivateUI });
       if (!parentWindow) {
         Components.utils.reportError(

--- a/mobile/android/components/DownloadManagerUI.js
+++ b/mobile/android/components/DownloadManagerUI.js
@@ -12,17 +12,17 @@ Components.utils.import("resource://gre/
 // Download Manager UI
 // -----------------------------------------------------------------------
 
 function DownloadManagerUI() { }
 
 DownloadManagerUI.prototype = {
   classID: Components.ID("{93db15b1-b408-453e-9a2b-6619e168324a}"),
 
-  show: function show(aWindowContext, aID, aReason, aUsePrivateUI) {
+  show: function show(aWindowContext, aDownload, aReason, aUsePrivateUI) {
     if (!aReason)
       aReason = Ci.nsIDownloadManagerUI.REASON_USER_INTERACTED;
 
     this._getBrowserApp().selectOrOpenTab("about:downloads");
   },
 
   get visible() {
     let browserApp = this._getBrowserApp();

--- a/toolkit/components/downloads/nsDownloadManager.cpp
+++ b/toolkit/components/downloads/nsDownloadManager.cpp
@@ -2477,17 +2477,17 @@ nsDownloadManager::Observe(nsISupports *
            nsDependentString(aData).EqualsLiteral(NS_IOSERVICE_ONLINE)) {
     // We can now resume all downloads that are supposed to auto-resume.
     (void)ResumeAllDownloads(false);
   }
   else if (strcmp(aTopic, "alertclickcallback") == 0) {
     nsCOMPtr<nsIDownloadManagerUI> dmui =
       do_GetService("@mozilla.org/download-manager-ui;1", &rv);
     NS_ENSURE_SUCCESS(rv, rv);
-    return dmui->Show(nullptr, 0, nsIDownloadManagerUI::REASON_USER_INTERACTED,
+    return dmui->Show(nullptr, nullptr, nsIDownloadManagerUI::REASON_USER_INTERACTED,
                       aData && NS_strcmp(aData, NS_LITERAL_STRING("private").get()) == 0);
   } else if (strcmp(aTopic, "sleep_notification") == 0 ||
              strcmp(aTopic, "suspend_process_notification") == 0) {
     // Pause downloads if we're sleeping, and mark the downloads as auto-resume
     (void)PauseAllDownloads(true);
   } else if (strcmp(aTopic, "wake_notification") == 0 ||
              strcmp(aTopic, "resume_process_notification") == 0) {
     int32_t resumeOnWakeDelay = 10000;

--- a/toolkit/components/downloads/nsDownloadManagerUI.js
+++ b/toolkit/components/downloads/nsDownloadManagerUI.js
@@ -19,17 +19,17 @@ const PREF_FLASH_COUNT = "browser.downlo
 function nsDownloadManagerUI() {}
 
 nsDownloadManagerUI.prototype = {
   classID: Components.ID("7dfdf0d1-aff6-4a34-bad1-d0fe74601642"),
 
   //////////////////////////////////////////////////////////////////////////////
   //// nsIDownloadManagerUI
 
-  show: function show(aWindowContext, aID, aReason, aUsePrivateUI)
+  show: function show(aWindowContext, aDownload, aReason, aUsePrivateUI)
   {
     if (!aReason)
       aReason = Ci.nsIDownloadManagerUI.REASON_USER_INTERACTED;
 
     // First we see if it is already visible
     let window = this.recentWindow;
     if (window) {
       window.focus();
@@ -47,25 +47,17 @@ nsDownloadManagerUI.prototype = {
     // browser.download.manager.closeWhenDone is set to true.
     try {
       if (aWindowContext)
         parent = aWindowContext.getInterface(Ci.nsIDOMWindow);
     } catch (e) { /* it's OK to not have a parent window */ }
 
     // We pass the download manager and the nsIDownload we want selected (if any)
     var params = Cc["@mozilla.org/array;1"].createInstance(Ci.nsIMutableArray);
-
-    // Don't fail if our passed in ID is invalid
-    var download = null;
-    try {
-      let dm = Cc["@mozilla.org/download-manager;1"].
-               getService(Ci.nsIDownloadManager);
-      download = dm.getDownload(aID);
-    } catch (ex) {}
-    params.appendElement(download, false);
+    params.appendElement(aDownload, false);
 
     // Pass in the reason as well
     let reason = Cc["@mozilla.org/supports-PRInt16;1"].
                  createInstance(Ci.nsISupportsPRInt16);
     reason.data = aReason;
     params.appendElement(reason, false);
 
     var ww = Cc["@mozilla.org/embedcomp/window-watcher;1"].

--- a/toolkit/components/downloads/nsDownloadProxy.h
+++ b/toolkit/components/downloads/nsDownloadProxy.h
@@ -47,35 +47,32 @@ public:
     NS_ENSURE_SUCCESS(rv, rv);
     nsCOMPtr<nsIPrefBranch> branch = do_QueryInterface(prefs);
 
     bool showDM = true;
     if (branch)
       branch->GetBoolPref(PREF_BDM_SHOWWHENSTARTING, &showDM);
 
     if (showDM) {
-      uint32_t id;
-      mInner->GetId(&id);
-
       nsCOMPtr<nsIDownloadManagerUI> dmui =
         do_GetService("@mozilla.org/download-manager-ui;1", &rv);
       NS_ENSURE_SUCCESS(rv, rv);
 
       bool visible;
       rv = dmui->GetVisible(&visible);
       NS_ENSURE_SUCCESS(rv, rv);
 
       bool focusWhenStarting = true;
       if (branch)
         (void)branch->GetBoolPref(PREF_BDM_FOCUSWHENSTARTING, &focusWhenStarting);
 
       if (visible && !focusWhenStarting)
         return NS_OK;
 
-      return dmui->Show(nullptr, id, nsIDownloadManagerUI::REASON_NEW_DOWNLOAD, aIsPrivate);
+      return dmui->Show(nullptr, mInner, nsIDownloadManagerUI::REASON_NEW_DOWNLOAD, aIsPrivate);
     }
     return rv;
   }
 
   NS_IMETHODIMP OnStateChange(nsIWebProgress* aWebProgress,
                               nsIRequest* aRequest, uint32_t aStateFlags,
                               nsresult aStatus)
   {

--- a/toolkit/components/downloads/nsIDownloadManagerUI.idl
+++ b/toolkit/components/downloads/nsIDownloadManagerUI.idl
@@ -1,16 +1,17 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsISupports.idl"
 interface nsIInterfaceRequestor;
+interface nsIDownload;
 
-[scriptable, uuid(bc54ef90-5215-11e2-bcfd-0800200c9a66)]
+[scriptable, uuid(0c76d4cf-0b06-4c1a-9bea-520c7bbdba99)]
 interface nsIDownloadManagerUI : nsISupports {
   /**
    * The reason that should be passed when the user requests to show the
    * download manager's UI.
    */
   const short REASON_USER_INTERACTED = 0;
 
   /**
@@ -19,28 +20,28 @@ interface nsIDownloadManagerUI : nsISupp
    */
   const short REASON_NEW_DOWNLOAD = 1;
 
  /**
   * Shows the Download Manager's UI to the user.
   *
   * @param [optional] aWindowContext
   *        The parent window context to show the UI.
-  * @param [optional] aID
-  *        The id of the download to be preselected upon opening.
+  * @param [optional] aDownload
+  *        The download to be preselected upon opening.
   * @param [optional] aReason
   *        The reason to show the download manager's UI.  This defaults to
   *        REASON_USER_INTERACTED, and should be one of the previously listed
   *        constants.
   * @param [optional] aUsePrivateUI
   *        Pass true as this argument to hint to the implementation that it
   *        should only display private downloads in the UI, if possible.
   */
   void show([optional] in nsIInterfaceRequestor aWindowContext,
-            [optional] in unsigned long aID,
+            [optional] in nsIDownload aDownload,
             [optional] in short aReason,
             [optional] in boolean aUsePrivateUI);
 
  /**
   * Indicates if the UI is visible or not.
   */
   readonly attribute boolean visible;