cros: Enable DesksBentoTest.VisibleOnAllDesksActiveDeskRemoval.

This test was disabled by crrev.com/2616228 since the test was flaky.
This is because the RootWindowDeskSwitchAnimator fails to take a
screenshot due to the remove animation starting after the test ends.

This CL re-enables the test and fixes it by using the RemoveDesk()
fcn from desks_test_util.h instead of DesksController::RemoveDesk().
This makes the test wait for the desk remobal animation.

Test: manual
Bug: 1164381
Change-Id: I0970e333f3593c8265acbe276e85b6ab91d2ade2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2615353Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Jeremy Chinsen <chinsenj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841631}

ash/wm/desks/desks_unittests.cc

@@ -3935,7 +3935,7 @@ TEST_F(DesksBentoTest, VisibleOnAllDesksGlobalZOrder) {
 
 // Tests the behavior of windows that are visible on all desks when the active
 // desk is removed.
-TEST_F(DesksBentoTest, DISABLED_VisibleOnAllDesksActiveDeskRemoval) {
+TEST_F(DesksBentoTest, VisibleOnAllDesksActiveDeskRemoval) {
   auto* controller = DesksController::Get();
   NewDesk();
   const Desk* desk_1 = controller->desks()[0].get();
@@ -3955,7 +3955,7 @@ TEST_F(DesksBentoTest, DISABLED_VisibleOnAllDesksActiveDeskRemoval) {
 
   // Remove the active desk. The visible on all desks windows should be on
   // |desk_2|.
-  controller->RemoveDesk(desk_1, DesksCreationRemovalSource::kKeyboard);
+  RemoveDesk(desk_1);
   auto desk_2_children = desk_2->GetDeskContainerForRoot(root)->children();
   EXPECT_EQ(2u, desk_2_children.size());
   EXPECT_TRUE(IsStackedBelow(win0.get(), win1.get()));