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

content/browser/download/download_file_factory.cc

Index: content/browser/download/download_file_factory.cc
diff --git a/content/browser/download/download_file_factory.cc b/content/browser/download/download_file_factory.cc
index 0b09c7b99867c375a2931acc138daf504af80966..206ada2d83326f123c72502a09ccb9d5426dc9c9 100644
--- a/content/browser/download/download_file_factory.cc
+++ b/content/browser/download/download_file_factory.cc
@@ -13,17 +13,12 @@ namespace content {
 DownloadFileFactory::~DownloadFileFactory() {}
 
 DownloadFile* DownloadFileFactory::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) {
-  return new DownloadFileImpl(save_info, default_downloads_directory, url,
-                              referrer_url, calculate_hash, std::move(file),
+  return new DownloadFileImpl(std::move(save_info), default_downloads_directory,
                               std::move(byte_stream), bound_net_log, observer);
 }