Apply new WM shadows to app list.

ui/app_list/views/app_list_view_observer.h

-// Copyright 2013 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_APP_LIST_VIEWS_APP_LIST_VIEW_OBSERVER_H_
-#define UI_APP_LIST_VIEWS_APP_LIST_VIEW_OBSERVER_H_
-
-namespace views {
-class Widget;
-}
-
-namespace app_list {
-
-class AppListViewObserver {
- public:
-  virtual void OnActivationChanged(views::Widget* widget, bool active) = 0;
-
- protected:
-  virtual ~AppListViewObserver() {}
-};
-
-}  // namespace app_list
-
-#endif  // UI_APP_LIST_VIEWS_APP_LIST_VIEW_OBSERVER_H_