Change DownloadProcessHandle to be more of an encapsulated class.

chrome/browser/download/download_file.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_FILE_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_FILE_H_
 #pragma once
 
 #include <string>
 
@@ skipping 11 matching lines @@
 // operations for one download. These objects live only for the duration that
 // the download is 'in progress': once the download has been completed or
 // cancelled, the DownloadFile is destroyed.
 class DownloadFile : public BaseFile {
  public:
   DownloadFile(const DownloadCreateInfo* info,
                DownloadManager* download_manager);
   virtual ~DownloadFile();
 
   // Cancels the download request associated with this file.
-  void CancelDownloadRequest(ResourceDispatcherHost* rdh);
+  void CancelDownloadRequest();
 
   int id() const { return id_; }
   DownloadManager* GetDownloadManager();
 
   virtual std::string DebugString() const;
 
  private:
   // The unique identifier for this download, assigned at creation by
   // the DownloadFileManager for its internal record keeping.
   int id_;
 
   // The handle to the process information.  Used for operations outside the
   // download system, specifically canceling a download.
   DownloadProcessHandle process_handle_;
 
   // DownloadManager this download belongs to.
   scoped_refptr<DownloadManager> download_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadFile);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_FILE_H_