We have a problem in the process on destroying WebContentsImpl because

chrome/browser/history/history_tab_helper.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_HISTORY_TAB_HELPER_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_TAB_HELPER_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
 #include "content/public/browser/web_contents_observer.h"
@@ skipping 33 matching lines @@
 
   // content::WebContentsObserver implementation.
   virtual void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) OVERRIDE;
   virtual void DidNavigateAnyFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) OVERRIDE;
   virtual void TitleWasSet(content::NavigationEntry* entry,
                            bool explicit_set) OVERRIDE;
-  virtual void WebContentsDestroyed(content::WebContents* tab) OVERRIDE;
+  virtual void WebContentsDestroyed() OVERRIDE;
 
   // Helper function to return the history service.  May return NULL.
   HistoryService* GetHistoryService();
 
   // Whether we have a (non-empty) title for the current page.
   // Used to prevent subsequent title updates from affecting history. This
   // prevents some weirdness because some AJAXy apps use titles for status
   // messages.
   bool received_page_title_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryTabHelper);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_TAB_HELPER_H_