We have a problem in the process on destroying WebContentsImpl because

chrome/browser/ui/views/hung_renderer_view.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_UI_VIEWS_HUNG_RENDERER_VIEW_H_
 #define CHROME_BROWSER_UI_VIEWS_HUNG_RENDERER_VIEW_H_
 
 #include "base/memory/scoped_vector.h"
 #include "chrome/browser/favicon/favicon_tab_helper.h"
 #include "content/public/browser/web_contents_observer.h"
@@ skipping 57 matching lines @@
     content::WebContents* web_contents() const {
       return content::WebContentsObserver::web_contents();
     }
 
     FaviconTabHelper* favicon_tab_helper() {
       return FaviconTabHelper::FromWebContents(web_contents());
     }
 
     // WebContentsObserver overrides:
     virtual void RenderProcessGone(base::TerminationStatus status) OVERRIDE;
-    virtual void WebContentsDestroyed(content::WebContents* tab) OVERRIDE;
+    virtual void WebContentsDestroyed() OVERRIDE;
 
    private:
     HungPagesTableModel* model_;
 
     DISALLOW_COPY_AND_ASSIGN(WebContentsObserverImpl);
   };
 
   // Invoked when a WebContents is destroyed. Cleans up |tab_observers_| and
   // notifies the observer and delegate.
   void TabDestroyed(WebContentsObserverImpl* tab);
@@ skipping 76 matching lines @@
   // Whether or not we've created controls for ourself.
   bool initialized_;
 
   // An amusing icon image.
   static gfx::ImageSkia* frozen_icon_;
 
   DISALLOW_COPY_AND_ASSIGN(HungRendererDialogView);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_HUNG_RENDERER_VIEW_H_