Fix typo in DragWindowFromShelfControllerTest.CancelDragDismissOverview

As suggested in:
https://chromium-review.googlesource.com/c/chromium/src/+/1903756

TBR=sky@chromium.org

Bug: 1022319
Change-Id: I31474c0f0242ca5177ef2bfca9b2415c6448f437
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1904543Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Commit-Queue: Hongchan Choi <hongchan@chromium.org>
Auto-Submit: Hongchan Choi <hongchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713665}

ash/home_screen/drag_window_from_shelf_controller_unittest.cc

@@ -518,7 +518,7 @@ TEST_F(DragWindowFromShelfControllerTest, NoBackdropDuringWindowScaleDown) {
 
 // Test that if drag is cancelled, overview should be dismissed and other
 // hidden windows should restore to its previous visibility state.
-// Flaky on ChromeOS. https://crbug.com/1022319
+// TODO(crbug.com/1022319): flaky.
 TEST_F(DragWindowFromShelfControllerTest, DISABLED_CancelDragDismissOverview) {
   auto window3 = CreateTestWindow();
   auto window2 = CreateTestWindow();