Make code compile with clang_use_chrome_plugin (part III)

xfa/fxbarcode/BC_BufferedImageLuminanceSource.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_BC_BUFFEREDIMAGELUMINANCESOURCE_H_
 #define XFA_FXBARCODE_BC_BUFFEREDIMAGELUMINANCESOURCE_H_
 
 #include "core/fxcrt/include/fx_basic.h"
 #include "core/fxcrt/include/fx_string.h"
 #include "core/fxge/include/fx_dib.h"
 #include "xfa/fxbarcode/BC_LuminanceSource.h"
 
 class CBC_BufferedImageLuminanceSource : public CBC_LuminanceSource {
  public:
   explicit CBC_BufferedImageLuminanceSource(const CFX_WideString& filename);
   explicit CBC_BufferedImageLuminanceSource(CFX_DIBitmap* pBitmap);
-  virtual ~CBC_BufferedImageLuminanceSource();
+  ~CBC_BufferedImageLuminanceSource() override;
 
-  CFX_ByteArray* GetRow(int32_t y, CFX_ByteArray& row, int32_t& e);
-  CFX_ByteArray* GetMatrix();
+  // CBC_LuminanceSource
+  CFX_ByteArray* GetRow(int32_t y, CFX_ByteArray& row, int32_t& e) override;
+  CFX_ByteArray* GetMatrix() override;
+
   virtual void Init(int32_t& e);
 
  private:
   int32_t m_bytesPerLine;
   int32_t m_left;
   int32_t m_top;
   CFX_Int32Array m_rgbData;
   CFX_DIBitmap* m_pBitmap;
   const CFX_WideString m_filename;
 };
 
 #endif  // XFA_FXBARCODE_BC_BUFFEREDIMAGELUMINANCESOURCE_H_