Cleanup: Remove unneeded forward declarations from various chrome/browser subdirectories.

chrome/browser/download/download_throttling_resource_handler.h

 // Copyright (c) 2011 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_THROTTLING_RESOURCE_HANDLER_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_THROTTLING_RESOURCE_HANDLER_H_
 #pragma once
 
 #include <string>
 
 #include "chrome/browser/download/download_request_limiter.h"
 #include "content/browser/renderer_host/resource_handler.h"
 #include "googleurl/src/gurl.h"
 
-class DownloadResourceHandler;
 class ResourceDispatcherHost;
 
 namespace net {
 class URLRequest;
 }  // namespace net
 
 // DownloadThrottlingResourceHandler is used to determine if a download should
 // be allowed. When a DownloadThrottlingResourceHandler is created it pauses the
 // download and asks the DownloadRequestLimiter if the download should be
 // allowed. The DownloadRequestLimiter notifies us asynchronously as to whether
@@ skipping 63 matching lines @@
   int tmp_buffer_length_;
 
   // Have we received OnRequestClosed()?  If so, we shouldn't act on
   // CancelDownload()/ContinueDownload().
   bool request_closed_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadThrottlingResourceHandler);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_THROTTLING_RESOURCE_HANDLER_H_