Add method for identifying different InfoBars

chrome/browser/nacl_host/nacl_infobar_delegate.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_NACL_HOST_NACL_INFOBAR_DELEGATE_H_
 #define CHROME_BROWSER_NACL_HOST_NACL_INFOBAR_DELEGATE_H_
 
 #include "components/infobars/core/confirm_infobar_delegate.h"
 
 class NaClInfoBarDelegate : public ConfirmInfoBarDelegate {
  public:
   // Creates a NaCl infobar and delegate and adds the infobar to the infobar
   // service corresponding to the given render process and view IDs.
   static void Create(int render_process_id, int render_view_id);
 
  private:
   NaClInfoBarDelegate();
   ~NaClInfoBarDelegate() override;
 
+  std::string GetIdentifier() const override;
   base::string16 GetMessageText() const override;
   int GetButtons() const override;
   base::string16 GetLinkText() const override;
   GURL GetLinkURL() const override;
 
   DISALLOW_COPY_AND_ASSIGN(NaClInfoBarDelegate);
 };
 
 #endif  // CHROME_BROWSER_NACL_HOST_NACL_INFOBAR_DELEGATE_H_