Remove unused m_nTabOrder in CPDFSDK_Annot.

fpdfsdk/include/cpdfsdk_annot.h

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef FPDFSDK_INCLUDE_CPDFSDK_ANNOT_H_
 #define FPDFSDK_INCLUDE_CPDFSDK_ANNOT_H_
 
 #include "core/fpdfdoc/include/cpdf_aaction.h"
@@ skipping 35 matching lines @@
 
   UnderlyingPageType* GetUnderlyingPage();
   CPDF_Page* GetPDFPage();
 #ifdef PDF_ENABLE_XFA
   CPDFXFA_Page* GetPDFXFAPage();
 #endif  // PDF_ENABLE_XFA
 
   void SetPage(CPDFSDK_PageView* pPageView);
   CPDFSDK_PageView* GetPageView() const { return m_pPageView; }
 
-  int GetTabOrder();
-  void SetTabOrder(int iTabOrder);
-
   FX_BOOL IsSelected();
   void SetSelected(FX_BOOL bSelected);
 
  protected:
   CPDFSDK_PageView* m_pPageView;
   FX_BOOL m_bSelected;
-  int m_nTabOrder;
 };
 
 #endif  // FPDFSDK_INCLUDE_CPDFSDK_ANNOT_H_