Changes to add duration into history database.

chrome/browser/history/archived_database.h

Index: chrome/browser/history/archived_database.h
diff --git a/chrome/browser/history/archived_database.h b/chrome/browser/history/archived_database.h
index 053a490627c2821b1987fa6991bbe48293b5f2fb..5ab83a64452c90b63c27ff15a1fb55fa38ef2a20 100644
--- a/chrome/browser/history/archived_database.h
+++ b/chrome/browser/history/archived_database.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -39,6 +39,9 @@ class ArchivedDatabase : public URLDatabase,
   void BeginTransaction();
   void CommitTransaction();
 
+  // Returns the current version that we will generate archived databases with.
+  static int GetCurrentVersion();
+
  private:
   // Implemented for the specialized databases.
   virtual sql::Connection& GetDB() OVERRIDE;