--- a/toolkit/components/downloads/src/nsDownloadManager.cpp
+++ b/toolkit/components/downloads/src/nsDownloadManager.cpp
@@ -1347,17 +1347,17 @@ nsDownloadManager::GetDefaultDownloadsDi
   rv = dirService->Get(NS_OS_HOME_DIR,
                        NS_GET_IID(nsILocalFile),
                        getter_AddRefs(downloadDir));
   NS_ENSURE_SUCCESS(rv, rv);
   rv = downloadDir->Append(folderName);
   NS_ENSURE_SUCCESS(rv, rv);
 #endif
 
-  downloadDir.swap(*aResult);
+  downloadDir.forget(aResult);
 
   return NS_OK;
 }
 
 #define NS_BRANCH_DOWNLOAD     "browser.download."
 #define NS_PREF_FOLDERLIST     "folderList"
 #define NS_PREF_DIR            "dir"
 
@@ -1389,17 +1389,17 @@ nsDownloadManager::GetUserDownloadsDirec
         nsCOMPtr<nsILocalFile> downloadDir;
         nsCOMPtr<nsIProperties> dirService =
            do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv);
         NS_ENSURE_SUCCESS(rv, rv);
         rv = dirService->Get(NS_OS_DESKTOP_DIR,
                              NS_GET_IID(nsILocalFile),
                              getter_AddRefs(downloadDir));
         NS_ENSURE_SUCCESS(rv, rv);
-        downloadDir.swap(*aResult);
+        downloadDir.forget(aResult);
         return NS_OK;
       }
       break;
     case 1: // Downloads
       return GetDefaultDownloadsDirectory(aResult);
     case 2: // Custom
       {
         nsCOMPtr<nsILocalFile> customDirectory;
@@ -1408,31 +1408,31 @@ nsDownloadManager::GetUserDownloadsDirec
                                     getter_AddRefs(customDirectory));
         if (customDirectory) {
           PRBool exists = PR_FALSE;
           (void)customDirectory->Exists(&exists);
 
           if (!exists) {
             rv = customDirectory->Create(nsIFile::DIRECTORY_TYPE, 0755);
             if (NS_SUCCEEDED(rv)) {
-              customDirectory.swap(*aResult);
+              customDirectory.forget(aResult);
               return NS_OK;
             }
 
             // Create failed, so it still doesn't exist.  Fall out and get the
             // default downloads directory.
           }
 
           PRBool writable = PR_FALSE;
           PRBool directory = PR_FALSE;
           (void)customDirectory->IsWritable(&writable);
           (void)customDirectory->IsDirectory(&directory);
 
           if (exists && writable && directory) {
-            customDirectory.swap(*aResult);
+            customDirectory.forget(aResult);
             return NS_OK;
           }
         }
         rv = GetDefaultDownloadsDirectory(aResult);
         if (NS_SUCCEEDED(rv)) {
           (void)prefBranch->SetComplexValue(NS_PREF_DIR,
                                             NS_GET_IID(nsILocalFile),
                                             *aResult);