It is time.

ui/base/models/table_model_observer.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_BASE_MODELS_TABLE_MODEL_OBSERVER_H_
-#define UI_BASE_MODELS_TABLE_MODEL_OBSERVER_H_
-
-#include "ui/base/ui_base_export.h"
-
-namespace ui {
-
-// Observer for a TableModel. Anytime the model changes, it must notify its
-// observer.
-class UI_BASE_EXPORT TableModelObserver {
- public:
-  // Invoked when the model has been completely changed.
-  virtual void OnModelChanged() = 0;
-
-  // Invoked when a range of items has changed.
-  virtual void OnItemsChanged(int start, int length) = 0;
-
-  // Invoked when new items are added.
-  virtual void OnItemsAdded(int start, int length) = 0;
-
-  // Invoked when a range of items has been removed.
-  virtual void OnItemsRemoved(int start, int length) = 0;
-
- protected:
-  virtual ~TableModelObserver() {}
-};
-
-}  // namespace ui
-
-#endif  // UI_BASE_MODELS_TABLE_MODEL_OBSERVER_H_