ui: Cleanup class/struct forward declarations

ui/app_list/views/folder_header_view.h

 // Copyright (c) 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_FOLDER_HEADER_VIEW_H_
 #define UI_APP_LIST_VIEWS_FOLDER_HEADER_VIEW_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "ui/app_list/app_list_export.h"
 #include "ui/app_list/app_list_item_observer.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/textfield/textfield_controller.h"
 #include "ui/views/view.h"
 
-namespace views {
-class ImageButton;
-}  // namespace views
-
 namespace app_list {
 
 class AppListFolderItem;
-class AppListFolderView;
 class FolderHeaderViewDelegate;
 
 namespace test {
 class FolderHeaderViewTest;
 }
 
 // FolderHeaderView contains a back button and an editable folder name field.
 class APP_LIST_EXPORT FolderHeaderView : public views::View,
                                          public views::TextfieldController,
                                          public views::ButtonListener,
@@ skipping 52 matching lines @@
   FolderHeaderViewDelegate* delegate_;
 
   bool folder_name_visible_;
 
   DISALLOW_COPY_AND_ASSIGN(FolderHeaderView);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_VIEWS_FOLDER_HEADER_VIEW_H_