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 9f48d740ea2eda1e59900dcfde2a3d96b9b6f5b2..fa0d0bedec44535a9336bd958d6f94db991ce274 100644
--- a/ash/shelf/shelf_layout_manager_unittest.cc
+++ b/ash/shelf/shelf_layout_manager_unittest.cc
@@ -1701,7 +1701,7 @@ TEST_F(ShelfLayoutManagerTest, ShelfAnimatesWhenGestureComplete) {
   {
     // Enable animations so that we can make sure that they occur.
     ui::ScopedAnimationDurationScaleMode regular_animations(
-        ui::ScopedAnimationDurationScaleMode::NORMAL_DURATION);
+        ui::ScopedAnimationDurationScaleMode::TEST_DURATION);
 
     aura::test::EventGenerator generator(Shell::GetPrimaryRootWindow());
     gfx::Rect shelf_bounds_in_screen =
@@ -1730,7 +1730,7 @@ TEST_F(ShelfLayoutManagerTest, ShelfAnimatesWhenGestureComplete) {
   {
     // Enable the animations so that we can make sure they do occur.
     ui::ScopedAnimationDurationScaleMode regular_animations(
-        ui::ScopedAnimationDurationScaleMode::NORMAL_DURATION);
+        ui::ScopedAnimationDurationScaleMode::TEST_DURATION);
 
     gfx::Point start =
         GetShelfWidget()->GetWindowBoundsInScreen().CenterPoint();