It is time.

ui/aura/layout_manager.h

-// 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.
-
-#ifndef UI_AURA_LAYOUT_MANAGER_H_
-#define UI_AURA_LAYOUT_MANAGER_H_
-
-#include "base/basictypes.h"
-#include "ui/aura/aura_export.h"
-
-namespace gfx {
-class Rect;
-}
-
-namespace aura {
-class Window;
-
-// An interface implemented by an object that places child windows.
-class AURA_EXPORT LayoutManager {
- public:
-  LayoutManager();
-  virtual ~LayoutManager();
-
-  // Invoked when the window is resized.
-  virtual void OnWindowResized() = 0;
-
-  // Invoked when the window |child| has been added.
-  virtual void OnWindowAddedToLayout(Window* child) = 0;
-
-  // Invoked prior to removing |window|.
-  virtual void OnWillRemoveWindowFromLayout(Window* child) = 0;
-
-  // Invoked after removing |window|.
-  virtual void OnWindowRemovedFromLayout(Window* child) = 0;
-
-  // Invoked when the |SetVisible()| is invoked on the window |child|.
-  // |visible| is the value supplied to |SetVisible()|. If |visible| is true,
-  // window->IsVisible() may still return false. See description in
-  // Window::IsVisible() for details.
-  virtual void OnChildWindowVisibilityChanged(Window* child, bool visible) = 0;
-
-  // Invoked when |Window::SetBounds| is called on |child|.
-  // Implementation must call |SetChildBoundsDirect| to change the
-  // |child|'s bounds. LayoutManager may modify |requested_bounds|
-  // before applying, or ignore the request.
-  virtual void SetChildBounds(Window* child,
-                              const gfx::Rect& requested_bounds) = 0;
-
- protected:
-  // Sets the child's bounds forcibly. LayoutManager is responsible
-  // for checking the state and make sure the bounds are correctly
-  // adjusted.
-  void SetChildBoundsDirect(aura::Window* child, const gfx::Rect& bounds);
-};
-
-}  // namespace aura
-
-#endif  // UI_AURA_LAYOUT_MANAGER_H_