[Downloads] Rework how hashes are calculated for download files.

content/browser/download/download_file_factory.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 CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_FACTORY_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_FACTORY_H_
 
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "content/common/content_export.h"
 #include "url/gurl.h"
 
+namespace crypto {
+class SecureHash;
+}
+
 namespace net {
 class BoundNetLog;
 }
 
 namespace content {
 
 class ByteStreamReader;
 class DownloadDestinationObserver;
 class DownloadFile;
 class DownloadManager;
 struct DownloadSaveInfo;
 
 class CONTENT_EXPORT DownloadFileFactory {
  public:
   virtual ~DownloadFileFactory();
 
   virtual DownloadFile* CreateFile(
-      const DownloadSaveInfo& save_info,
+      scoped_ptr<DownloadSaveInfo> save_info,
       const base::FilePath& default_downloads_directory,
-      const GURL& url,
-      const GURL& referrer_url,
-      bool calculate_hash,
-      base::File file,
       scoped_ptr<ByteStreamReader> byte_stream,
       const net::BoundNetLog& bound_net_log,
       base::WeakPtr<DownloadDestinationObserver> observer);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_FACTORY_H_