Revert of Introduce NON_ZERO_DURATION for animation unit tests

ash/shelf/shelf_layout_manager_unittest.cc

Index: ash/shelf/shelf_layout_manager_unittest.cc
diff --git a/ash/shelf/shelf_layout_manager_unittest.cc b/ash/shelf/shelf_layout_manager_unittest.cc
index a7144a51bd9e3d123368815003ee4f051a5cabb5..a6182ec016a8847785ca3194c10ebb8248d54292 100644
--- a/ash/shelf/shelf_layout_manager_unittest.cc
+++ b/ash/shelf/shelf_layout_manager_unittest.cc
@@ -1701,7 +1701,7 @@
   {
     // Enable animations so that we can make sure that they occur.
     ui::ScopedAnimationDurationScaleMode regular_animations(
-        ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
+        ui::ScopedAnimationDurationScaleMode::NORMAL_DURATION);
 
     ui::test::EventGenerator generator(Shell::GetPrimaryRootWindow());
     gfx::Rect shelf_bounds_in_screen =
@@ -1730,7 +1730,7 @@
   {
     // Enable the animations so that we can make sure they do occur.
     ui::ScopedAnimationDurationScaleMode regular_animations(
-        ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
+        ui::ScopedAnimationDurationScaleMode::NORMAL_DURATION);
 
     gfx::Point start =
         GetShelfWidget()->GetWindowBoundsInScreen().CenterPoint();