chrome: Cleanup class/struct forward declarations

chrome/browser/ui/views/frame/browser_non_client_frame_view_ash.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 CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_NON_CLIENT_FRAME_VIEW_ASH_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_NON_CLIENT_FRAME_VIEW_ASH_H_
 
 #include <memory>
 
 #include "ash/common/shell_observer.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "chrome/browser/ui/views/frame/browser_non_client_frame_view.h"
 #include "chrome/browser/ui/views/tab_icon_view_model.h"
 
 class TabIconView;
 class WebAppLeftHeaderView;
 
 namespace ash {
-class FrameCaptionButton;
 class FrameCaptionButtonContainerView;
 class HeaderPainter;
 }
 
-namespace views {
-class ImageButton;
-class ToggleImageButton;
-}
-
 class BrowserNonClientFrameViewAsh : public BrowserNonClientFrameView,
                                      public ash::ShellObserver,
                                      public TabIconViewModel {
  public:
   BrowserNonClientFrameViewAsh(BrowserFrame* frame, BrowserView* browser_view);
   ~BrowserNonClientFrameViewAsh() override;
 
   void Init();
 
   // BrowserNonClientFrameView:
@@ skipping 91 matching lines @@
   // For popups, the window icon.
   TabIconView* window_icon_;
 
   // Helper class for painting the header.
   std::unique_ptr<ash::HeaderPainter> header_painter_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserNonClientFrameViewAsh);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_NON_CLIENT_FRAME_VIEW_ASH_H_