Make code compile with clang_use_chrome_plugin (part III)

xfa/fxbarcode/datamatrix/BC_C40Encoder.h

 // Copyright 2014 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 XFA_FXBARCODE_DATAMATRIX_BC_C40ENCODER_H_
 #define XFA_FXBARCODE_DATAMATRIX_BC_C40ENCODER_H_
 
 #include "xfa/fxbarcode/datamatrix/BC_Encoder.h"
 
 class CBC_C40Encoder : public CBC_Encoder {
  public:
   CBC_C40Encoder();
-  virtual ~CBC_C40Encoder();
-  virtual int32_t getEncodingMode();
-  virtual void Encode(CBC_EncoderContext& context, int32_t& e);
+  ~CBC_C40Encoder() override;
+
+  // CBC_Encoder
+  int32_t getEncodingMode() override;
+  void Encode(CBC_EncoderContext& context, int32_t& e) override;
+
   static void writeNextTriplet(CBC_EncoderContext& context,
                                CFX_WideString& buffer);
+
   virtual void handleEOD(CBC_EncoderContext& context,
                          CFX_WideString& buffer,
                          int32_t& e);
   virtual int32_t encodeChar(FX_WCHAR c, CFX_WideString& sb, int32_t& e);
 
  private:
   int32_t backtrackOneCharacter(CBC_EncoderContext& context,
                                 CFX_WideString& buffer,
                                 CFX_WideString& removed,
                                 int32_t lastCharSize,
                                 int32_t& e);
   static CFX_WideString encodeToCodewords(CFX_WideString sb, int32_t startPos);
 };
 
 #endif  // XFA_FXBARCODE_DATAMATRIX_BC_C40ENCODER_H_