Use the new animation tween type for app list folder animation.

ui/app_list/views/folder_background_view.cc

Index: ui/app_list/views/folder_background_view.cc
diff --git a/ui/app_list/views/folder_background_view.cc b/ui/app_list/views/folder_background_view.cc
index ebb3c12f4ad9188b3ed41d96c8ce00bc1ecdc9b8..5c033728a8b3b2f5b9897b311db2d84982204968 100644
--- a/ui/app_list/views/folder_background_view.cc
+++ b/ui/app_list/views/folder_background_view.cc
@@ -55,9 +55,11 @@ void FolderBackgroundView::UpdateFolderContainerBubble(ShowState state) {
   settings.SetTransitionDuration(
       base::TimeDelta::FromMilliseconds((kBubbleTransitionDurationMs)));
   if (show_state_ == SHOW_BUBBLE) {
+    settings.SetTweenType(gfx::Tween::EASE_OUT_2);
     layer()->SetOpacity(1.0f);
     layer()->SetTransform(gfx::Transform());
   } else {
+    settings.SetTweenType(gfx::Tween::EASE_IN_3);
     layer()->SetOpacity(0.0f);
     layer()->SetTransform(transform);
   }