Prevent hiding a toast during animation

ash/system/toast/toast_manager_unittest.cc

Index: ash/system/toast/toast_manager_unittest.cc
diff --git a/ash/system/toast/toast_manager_unittest.cc b/ash/system/toast/toast_manager_unittest.cc
index f8d942b5bbbd6bb3ad8dff9359daa5ac1b38b216..ff74e16894d2f436e8000fa8ca54ccce309112b1 100644
--- a/ash/system/toast/toast_manager_unittest.cc
+++ b/ash/system/toast/toast_manager_unittest.cc
@@ -122,11 +122,14 @@ TEST_F(ToastManagerTest, ShowAndCloseManuallyDuringAnimation) {
   EXPECT_EQ(1, GetToastSerial());
   EXPECT_TRUE(GetCurrentWidget()->GetLayer()->GetAnimator()->is_animating());
 
-  // Close it during animation.
+  // Try to close it during animation.
   ClickDismissButton();
 
-  while (GetCurrentOverlay() != nullptr)
+  while (GetCurrentWidget()->GetLayer()->GetAnimator()->is_animating())
     base::RunLoop().RunUntilIdle();
+
+  // Toast isn't closed.
+  EXPECT_TRUE(GetCurrentOverlay() != nullptr);
 }
 
 TEST_F(ToastManagerTest, QueueMessage) {