Removes some dead database code

chrome/browser/history/history_tab_helper.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/history/history_tab_helper.h"
 
 #include <utility>
 
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_service_factory.h"
@@ skipping 136 matching lines @@
   Profile* profile =
       Profile::FromBrowserContext(web_contents()->GetBrowserContext());
   if (profile->IsOffTheRecord())
     return NULL;
 
   return HistoryServiceFactory::GetForProfile(profile,
                                               Profile::IMPLICIT_ACCESS);
 }
 
 void HistoryTabHelper::WebContentsDestroyed(WebContents* tab) {
-  // TODO(sky): nuke this since no one is using visit_duration (and this is all
-  // wrong).
-
   // We update the history for this URL.
   // The content returned from web_contents() has been destroyed by now.
   // We need to use tab value directly.
   Profile* profile = Profile::FromBrowserContext(tab->GetBrowserContext());
   if (profile->IsOffTheRecord())
     return;
 
   HistoryService* hs =
       HistoryServiceFactory::GetForProfile(profile, Profile::IMPLICIT_ACCESS);
   if (hs) {
     NavigationEntry* entry = tab->GetController().GetLastCommittedEntry();
     if (entry) {
       hs->UpdateWithPageEndTime(tab, entry->GetPageID(), tab->GetURL(),
                                 base::Time::Now());
     }
   }
 }