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

chrome/browser/extensions/extension_disabled_infobar_delegate.cc

 // 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.
 
 #include "chrome/browser/extensions/extension_disabled_infobar_delegate.h"
 
 #include "app/l10n_util.h"
 #include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/extensions/extension_file_util.h"
 #include "chrome/browser/extensions/extension_install_ui.h"
@@ skipping 124 matching lines @@
         break;
       }
       default:
         NOTREACHED();
     }
   }
 
  private:
   NotificationRegistrar registrar_;
   TabContents* tab_contents_;
-  ExtensionsService* service_;
+  scoped_refptr<ExtensionsService> service_;
   Extension* extension_;
 };
 
 void ShowExtensionDisabledUI(ExtensionsService* service, Profile* profile,
                              Extension* extension) {
   Browser* browser = BrowserList::GetLastActiveWithProfile(profile);
   if (!browser)
     return;
 
   TabContents* tab_contents = browser->GetSelectedTabContents();
   if (!tab_contents)
     return;
 
   tab_contents->AddInfoBar(new ExtensionDisabledInfobarDelegate(
       tab_contents, service, extension));
 }
 
 void ShowExtensionDisabledDialog(ExtensionsService* service, Profile* profile,
                                  Extension* extension) {
   // This object manages its own lifetime.
   new ExtensionDisabledDialogDelegate(profile, service, extension);
 }