ash: Rename LauncherModelObserver to ShelfModelObserver.

ash/launcher/launcher_model_observer.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 ASH_LAUNCHER_LAUNCHER_MODEL_OBSERVER_H_
-#define ASH_LAUNCHER_LAUNCHER_MODEL_OBSERVER_H_
-
-#include "ash/ash_export.h"
-#include "ash/launcher/launcher_types.h"
-
-namespace ash {
-
-struct LauncherItem;
-
-class ASH_EXPORT LauncherModelObserver {
- public:
-  // Invoked after an item has been added to the model.
-  virtual void LauncherItemAdded(int index) = 0;
-
-  // Invoked after an item has been removed. |index| is the index the item was
-  // at.
-  virtual void LauncherItemRemoved(int index, LauncherID id) = 0;
-
-  // Invoked after an item has been moved. See LauncherModel::Move() for details
-  // of the arguments.
-  virtual void LauncherItemMoved(int start_index, int target_index) = 0;
-
-  // Invoked when the state of an item changes. |old_item| is the item
-  // before the change.
-  virtual void LauncherItemChanged(int index, const LauncherItem& old_item) = 0;
-
-  // Invoked when launcher status is changed.
-  virtual void LauncherStatusChanged() = 0;
-
- protected:
-  virtual ~LauncherModelObserver() {}
-};
-
-}  // namespace ash
-
-#endif  // ASH_LAUNCHER_LAUNCHER_MODEL_OBSERVER_H_