Add the referrer url to the downloads table in the History database.

chrome/browser/history/download_database.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 CHROME_BROWSER_HISTORY_DOWNLOAD_DATABASE_H_
 #define CHROME_BROWSER_HISTORY_DOWNLOAD_DATABASE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 49 matching lines @@
 
   // Returns true if able to successfully rewrite the invalid values for the
   // |state| field from 3 to 4. Returns false if there was an error fixing the
   // database. See http://crbug.com/140687
   bool MigrateDownloadsState();
 
   // Returns true if able to successfully add the last interrupt reason and the
   // two target paths to downloads.
   bool MigrateDownloadsReasonPathsAndDangerType();
 
+  // Returns true if able to successfully add the referrer column to the
+  // downloads table.
+  bool MigrateReferrer();
+
   // Creates the downloads table if needed.
   bool InitDownloadTable();
 
   // Used to quickly clear the downloads. First you would drop it, then you
   // would re-initialize it.
   bool DropDownloadTable();
 
  private:
   FRIEND_TEST_ALL_PREFIXES(
       HistoryBackendDBTest, ConfirmDownloadInProgressCleanup);
@@ skipping 47 matching lines @@
   // doing the cleanup until after any DB migration and unless we are
   // actually use the downloads database.
   bool in_progress_entry_cleanup_completed_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadDatabase);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_DOWNLOAD_DATABASE_H_