Changes to add duration into history database.

chrome/browser/history/history_tab_helper.h

Index: chrome/browser/history/history_tab_helper.h
diff --git a/chrome/browser/history/history_tab_helper.h b/chrome/browser/history/history_tab_helper.h
index 9433600d415091f3d7593a5608c954188ac15776..57f9a54e00ee28a4b67481d53504e0526bc23c6d 100644
--- a/chrome/browser/history/history_tab_helper.h
+++ b/chrome/browser/history/history_tab_helper.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.
 
@@ -50,6 +50,7 @@ class HistoryTabHelper : public content::WebContentsObserver,
   virtual void DidNavigateAnyFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) OVERRIDE;
+  virtual void WebContentsDestroyed(content::WebContents* tab) OVERRIDE;
 
   // content::NotificationObserver implementation.
   virtual void Observe(int type,