Use a bezier timing function for the overview mode animation

ash/wm/overview/scoped_transform_overview_window.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 "ash/wm/overview/scoped_transform_overview_window.h"
 
 #include "ash/screen_util.h"
 #include "ash/shell.h"
 #include "ash/wm/overview/scoped_window_copy.h"
 #include "ash/wm/window_state.h"
@@ skipping 13 matching lines @@
 // The animation settings used for window selector animations.
 class WindowSelectorAnimationSettings
     : public ui::ScopedLayerAnimationSettings {
  public:
   WindowSelectorAnimationSettings(aura::Window* window) :
       ui::ScopedLayerAnimationSettings(window->layer()->GetAnimator()) {
     SetPreemptionStrategy(
         ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
     SetTransitionDuration(base::TimeDelta::FromMilliseconds(
         ScopedTransformOverviewWindow::kTransitionMilliseconds));
-    SetTweenType(gfx::Tween::EASE_OUT);
+    SetTweenType(gfx::Tween::EASE_OUT_BEZIER);
   }
 
   virtual ~WindowSelectorAnimationSettings() {
   }
 };
 
 void SetTransformOnWindow(aura::Window* window,
                           const gfx::Transform& transform,
                           bool animate) {
   if (animate) {
@@ skipping 215 matching lines @@
 }
 
 void ScopedTransformOverviewWindow::PrepareForOverview() {
   DCHECK(!overview_started_);
   overview_started_ = true;
   ash::wm::GetWindowState(window_)->set_ignored_by_shelf(true);
   RestoreWindow();
 }
 
 }  // namespace ash