chrome: Cleanup class/struct forward declarations

chrome/browser/ui/views/download/download_item_view.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.
 //
 // A view that implements one download on the Download shelf.
 // Each DownloadItemView contains an application icon, a text label
 // indicating the download's file name, a text label indicating the
 // download's status (such as the number of bytes downloaded so far)
 // and a button for canceling an in progress download, or opening
 // the completed download.
@@ skipping 36 matching lines @@
 class Image;
 class ImageSkia;
 class SlideAnimation;
 }
 
 namespace ui {
 class ThemeProvider;
 }
 
 namespace views {
-class ImageButton;
 class Label;
-class LabelButton;
 class MdTextButton;
 }
 
 // Represents a single download item on the download shelf. Encompasses an icon,
 // text, malicious download warnings, etc.
 class DownloadItemView : public views::InkDropHostView,
                          public views::VectorIconButtonDelegate,
                          public views::ContextMenuController,
                          public content::DownloadItem::Observer,
                          public gfx::AnimationDelegate {
@@ skipping 261 matching lines @@
   std::unique_ptr<extensions::ExperienceSamplingEvent> sampling_event_;
 
   // Method factory used to delay reenabling of the item when opening the
   // downloaded file.
   base::WeakPtrFactory<DownloadItemView> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItemView);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_DOWNLOAD_DOWNLOAD_ITEM_VIEW_H_