It is time.

ui/wm/public/animation_host.h

-// 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.
-
-#ifndef UI_WM_PUBLIC_ANIMATION_HOST_H_
-#define UI_WM_PUBLIC_ANIMATION_HOST_H_
-
-#include "base/compiler_specific.h"
-#include "ui/aura/aura_export.h"
-
-namespace gfx {
-class Vector2d;
-}
-
-namespace aura {
-class Window;
-namespace client {
-
-// Interface for top level window host of animation. Communicates additional
-// bounds required for animation as well as animation completion for deferring
-// window closes on hide.
-class AURA_EXPORT AnimationHost {
- public:
-  // Ensure the host window is at least this large so that transitions have
-  // sufficient space.
-  // The |top_left_delta| parameter contains the offset to be subtracted from
-  // the window bounds for the top left corner.
-  // The |bottom_right_delta| parameter contains the offset to be added to the
-  // window bounds for the bottom right.
-  virtual void SetHostTransitionOffsets(
-      const gfx::Vector2d& top_left_delta,
-      const gfx::Vector2d& bottom_right_delta) = 0;
-
-  // Called after the window has faded out on a hide.
-  virtual void OnWindowHidingAnimationCompleted() = 0;
-
- protected:
-  virtual ~AnimationHost() {}
-};
-
-AURA_EXPORT void SetAnimationHost(Window* window,
-                                  AnimationHost* animation_host);
-AURA_EXPORT AnimationHost* GetAnimationHost(Window* window);
-
-}  // namespace client
-}  // namespace aura
-
-#endif  // UI_WM_PUBLIC_ANIMATION_HOST_H_