Make sure that pointer to the ExtensionsService is valid in the extensions infobars.

chrome/browser/extensions/crashed_extension_infobar.h

 // Copyright (c) 2009 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_EXTENSIONS_CRASHED_EXTENSION_INFOBAR_H_
 #define CHROME_BROWSER_EXTENSIONS_CRASHED_EXTENSION_INFOBAR_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "chrome/browser/tab_contents/infobar_delegate.h"
 
 class Extension;
 class ExtensionsService;
 class SkBitmap;
 
 // This infobar will be displayed when an extension process crashes. It allows
 // the user to reload the crashed extension.
 class CrashedExtensionInfoBarDelegate : public ConfirmInfoBarDelegate {
  public:
   // |tab_contents| should point to the TabContents the infobar will be added
   // to. |extension| should be the crashed extension, and |extensions_service|
   // the ExtensionsService which manages that extension.
   CrashedExtensionInfoBarDelegate(TabContents* tab_contents,
                                   ExtensionsService* extensions_service,
                                   const Extension* extension);
+  ~CrashedExtensionInfoBarDelegate();
 
   // ConfirmInfoBarDelegate
   virtual std::wstring GetMessageText() const;
   virtual void InfoBarClosed();
   virtual SkBitmap* GetIcon() const;
   virtual int GetButtons() const;
   virtual std::wstring GetButtonLabel(
       ConfirmInfoBarDelegate::InfoBarButton button) const;
   virtual bool Accept();
 
  private:
-  ExtensionsService* extensions_service_;
+  scoped_refptr<ExtensionsService> extensions_service_;
 
   const std::string extension_id_;
   const std::string extension_name_;
 
   DISALLOW_COPY_AND_ASSIGN(CrashedExtensionInfoBarDelegate);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_CRASHED_EXTENSION_INFOBAR_H_