chrome: Cleanup class/struct forward declarations

chrome/browser/ui/views/frame/browser_non_client_frame_view_mus.h

 // Copyright 2015 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_MUS_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_NON_CLIENT_FRAME_VIEW_MUS_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "chrome/browser/ui/views/frame/browser_non_client_frame_view.h"
 #include "chrome/browser/ui/views/tab_icon_view_model.h"
 #include "chrome/browser/ui/views/tabs/tab_strip_observer.h"
 
 #if !defined(OS_CHROMEOS)
 #include "chrome/browser/ui/views/frame/avatar_button_manager.h"
 #endif
 
 class TabIconView;
 class WebAppLeftHeaderView;
 
 namespace ui {
 class Window;
 }
 
-namespace views {
-class ImageButton;
-class ToggleImageButton;
-}
-
 class BrowserNonClientFrameViewMus : public BrowserNonClientFrameView,
                                      public TabIconViewModel,
                                      public TabStripObserver {
  public:
   static const char kViewClassName[];
 
   BrowserNonClientFrameViewMus(BrowserFrame* frame, BrowserView* browser_view);
   ~BrowserNonClientFrameViewMus() override;
 
   void Init();
@@ skipping 95 matching lines @@
   // Wrapper around the in-frame avatar switcher.
   AvatarButtonManager profile_switcher_;
 #endif
 
   TabStrip* tab_strip_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserNonClientFrameViewMus);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_BROWSER_NON_CLIENT_FRAME_VIEW_MUS_H_