Re-enable DiscardDangerousFile in hopes that it is not flaky.

0816757e fixed a real issue which might be the source
of the flake here.

Bug: 810302
Change-Id: I38630563e11944deec2dcd71dc89a01eabdfdd74
Reviewed-on: https://chromium-review.googlesource.com/957806Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543199}

chrome/browser/download/notification/download_notification_interactive_uitest.cc

@@ -357,9 +357,7 @@ IN_PROC_BROWSER_TEST_F(DownloadNotificationTest, DownloadFile) {
   EXPECT_FALSE(GetNotification(notification_id()));
 }
 
-// Disabled due to timeouts; see https://crbug.com/810302.
-IN_PROC_BROWSER_TEST_F(DownloadNotificationTest,
-                       DISABLED_DownloadDangerousFile) {
+IN_PROC_BROWSER_TEST_F(DownloadNotificationTest, DownloadDangerousFile) {
   GURL download_url(
       embedded_test_server()->GetURL("/downloads/dangerous/dangerous.swf"));