It is time.

ui/views/controls/resize_area_delegate.h

-// Copyright (c) 2011 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_CONTROLS_RESIZE_AREA_DELEGATE_H_
-#define UI_VIEWS_CONTROLS_RESIZE_AREA_DELEGATE_H_
-
-namespace views {
-
-// An interface implemented by objects that want to be notified about the resize
-// event.
-class ResizeAreaDelegate {
- public:
-  // OnResize is sent when resizing is detected. |resize_amount| specifies the
-  // number of pixels that the user wants to resize by, and can be negative or
-  // positive (depending on direction of dragging and flips according to
-  // locale directionality: dragging to the left in LTR locales gives negative
-  // |resize_amount| but positive amount for RTL). |done_resizing| is true if
-  // the user has released the mouse.
-  virtual void OnResize(int resize_amount, bool done_resizing) = 0;
-
- protected:
-  virtual ~ResizeAreaDelegate() {}
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_CONTROLS_RESIZE_AREA_DELEGATE_H_