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

ui/app_list/views/apps_grid_view.cc

 // Copyright (c) 2012 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/apps_grid_view.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 
@@ skipping 658 matching lines @@
 void AppsGridView::ScheduleShowHideAnimation(bool show) {
   // Stop any previous animation.
   layer()->GetAnimator()->StopAnimating();
 
   // Set initial state.
   SetVisible(true);
   layer()->SetOpacity(show ? 0.0f : 1.0f);
 
   ui::ScopedLayerAnimationSettings animation(layer()->GetAnimator());
   animation.AddObserver(this);
-  animation.SetTweenType(gfx::Tween::EASE_IN_2);
+  animation.SetTweenType(
+      show ? kFolderFadeInTweenType : kFolderFadeOutTweenType);
   animation.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
       show ? kFolderTransitionInDurationMs : kFolderTransitionOutDurationMs));
 
   layer()->SetOpacity(show ? 1.0f : 0.0f);
 }
 
 void AppsGridView::InitiateDragFromReparentItemInRootLevelGridView(
     AppListItemView* original_drag_view,
     const gfx::Rect& drag_view_rect,
     const gfx::Point& drag_point) {
@@ skipping 1355 matching lines @@
 void AppsGridView::SetAsFolderDroppingTarget(const Index& target_index,
                                              bool is_target_folder) {
   AppListItemView* target_view =
       static_cast<AppListItemView*>(
           GetViewAtSlotOnCurrentPage(target_index.slot));
   if (target_view)
     target_view->SetAsAttemptedFolderTarget(is_target_folder);
 }
 
 }  // namespace app_list