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

chrome/browser/download/download_history_unittest.cc

 // 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.
 
 #include "chrome/browser/download/download_history.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <utility>
 #include <vector>
@@ skipping 206 matching lines @@
           row.url_chain,
           row.referrer_url,
           row.mime_type,
           row.original_mime_type,
           row.start_time,
           row.end_time,
           row.etag,
           row.last_modified,
           row.received_bytes,
           row.total_bytes,
+          std::string(),
           history::ToContentDownloadState(row.state),
           history::ToContentDownloadDangerType(row.danger_type),
           history::ToContentDownloadInterruptReason(row.interrupt_reason),
           row.opened);
       EXPECT_CALL(manager(), MockCreateDownloadItem(adapter))
         .WillOnce(DoAll(
             InvokeWithoutArgs(
                 this, &DownloadHistoryTest::CallOnDownloadCreatedInOrder),
             Return(&item(index))));
     }
@@ skipping 607 matching lines @@
   FinishCreateDownload();
   EXPECT_TRUE(DownloadHistory::IsPersisted(&item(0)));
 
   // ItemAdded should call OnDownloadUpdated, which should detect that the item
   // changed while it was being added and call UpdateDownload immediately.
   info.opened = true;
   ExpectDownloadUpdated(info);
 }
 
 }  // anonymous namespace