chrome: Cleanup class/struct forward declarations

chrome/browser/download/download_shelf.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_DOWNLOAD_DOWNLOAD_SHELF_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_SHELF_H_
 
 #include <stdint.h>
 
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 
 class Browser;
 
-namespace base {
-class TimeTicks;
-}
-
 namespace gfx {
 class Canvas;
-class ImageSkia;
-class Rect;
 }
 
 namespace content {
 class DownloadItem;
 class DownloadManager;
 }
 
 namespace ui {
 class ThemeProvider;
 }
@@ skipping 107 matching lines @@
   // download should belong to the DownloadManager returned by
   // GetDownloadManager().
   void ShowDownloadById(int32_t download_id);
 
   bool should_show_on_unhide_;
   bool is_hidden_;
   base::WeakPtrFactory<DownloadShelf> weak_ptr_factory_;
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_SHELF_H_