Update ShelfAnimatesToHiddenWhenGestureOutComplete

The test was timing out waiting for the auto-hidden shelf to get shown
while hovering the mouse pointer over it. This changes the test to use
swipe up gesture to show the shelf (which is used in other tests).

BUG=1000463

Change-Id: I4270215be79239eb2861bb08bfae0fd3fc386f16
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2214610Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771882}

ash/shelf/shelf_layout_manager_unittest.cc

@@ -1669,9 +1669,7 @@ TEST_P(ShelfLayoutManagerTest, ShelfAnimatesToVisibleWhenGestureInComplete) {
 
 // Tests that the shelf animates to the auto hidden bounds after a swipe down
 // on the visible shelf.
-// TODO(https://crbug.com/1000463): Flaky.
-TEST_P(ShelfLayoutManagerTest,
-       DISABLED_ShelfAnimatesToHiddenWhenGestureOutComplete) {
+TEST_P(ShelfLayoutManagerTest, ShelfAnimatesToHiddenWhenGestureOutComplete) {
   Shelf* shelf = GetPrimaryShelf();
   shelf->SetAutoHideBehavior(ShelfAutoHideBehavior::kAlways);
   EXPECT_EQ(SHELF_AUTO_HIDE, shelf->GetVisibilityState());
@@ -1691,10 +1689,8 @@ TEST_P(ShelfLayoutManagerTest,
     ui::test::EventGenerator* generator = GetEventGenerator();
 
     // Show the shelf first.
-    display::Display display =
-        display::Screen::GetScreen()->GetPrimaryDisplay();
     WidgetAnimationWaiter waiter1(GetShelfWidget(), visible_bounds);
-    generator->MoveMouseTo(display.bounds().bottom_center());
+    SwipeUpOnShelf();
     waiter1.WaitForAnimation();
     EXPECT_TRUE(waiter1.WasValidAnimation());
     EXPECT_EQ(SHELF_AUTO_HIDE_SHOWN, shelf->GetAutoHideState());