It is time.

ui/views/window/window_resources.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_VIEWS_WINDOW_WINDOW_RESOURCES_H_
-#define UI_VIEWS_WINDOW_WINDOW_RESOURCES_H_
-
-namespace gfx {
-class ImageSkia;
-}
-
-namespace views {
-
-typedef int FramePartImage;
-
-///////////////////////////////////////////////////////////////////////////////
-// WindowResources
-//
-//  An interface implemented by an object providing images to render the
-//  contents of a window frame. The Window may swap in different
-//  implementations of this interface to render different modes. The definition
-//  of FramePartImage depends on the implementation.
-//
-class WindowResources {
- public:
-  virtual ~WindowResources() {}
-
-  virtual gfx::ImageSkia* GetPartImage(FramePartImage part) const = 0;
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_WINDOW_WINDOW_RESOURCES_H_