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

ui/app_list/views/app_list_folder_view.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/app_list/views/app_list_folder_view.h"
 
 #include <algorithm>
 
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/app_list_folder_item.h"
@@ skipping 81 matching lines @@
   // Hide the top items temporarily if showing the view for opening the folder.
   if (show)
     items_grid_view_->SetTopItemViewsVisible(false);
 
   // Set initial state.
   layer()->SetOpacity(show ? 0.0f : 1.0f);
   SetVisible(true);
   UpdateFolderNameVisibility(true);
 
   ui::ScopedLayerAnimationSettings animation(layer()->GetAnimator());
-  animation.SetTweenType(gfx::Tween::EASE_IN_2);
+  animation.SetTweenType(
+      show ? kFolderFadeInTweenType : kFolderFadeOutTweenType);
   animation.AddObserver(this);
   animation.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
       show ? kFolderTransitionInDurationMs : kFolderTransitionOutDurationMs));
 
   layer()->SetOpacity(show ? 1.0f : 0.0f);
 }
 
 gfx::Size AppListFolderView::GetPreferredSize() {
   const gfx::Size header_size = folder_header_view_->GetPreferredSize();
   const gfx::Size grid_size = items_grid_view_->GetPreferredSize();
@@ skipping 154 matching lines @@
   container_view_->apps_grid_view()->
       EndDragFromReparentItemInRootLevel(events_forwarded_to_drag_drop_host);
 }
 
 void AppListFolderView::NavigateBack(AppListFolderItem* item,
                                      const ui::Event& event_flags) {
   container_view_->ShowApps(item);
 }
 
 }  // namespace app_list