Make code compile with clang_use_chrome_plugin (part III)

xfa/fxbarcode/oned/BC_OneDReader.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_ONED_BC_ONEDREADER_H_
 #define XFA_FXBARCODE_ONED_BC_ONEDREADER_H_
 
 #include "xfa/fxbarcode/BC_Reader.h"
 
 class CBC_BinaryBitmap;
 class CBC_CommonBitArray;
 
 class CBC_OneDReader : public CBC_Reader {
  public:
   CBC_OneDReader();
-  virtual ~CBC_OneDReader();
-  virtual CFX_ByteString Decode(CBC_BinaryBitmap* image, int32_t& e);
-  virtual CFX_ByteString Decode(CBC_BinaryBitmap* image,
-                                int32_t hints,
-                                int32_t& e);
+  ~CBC_OneDReader() override;
+
+  // CBC_Reader
+  CFX_ByteString Decode(CBC_BinaryBitmap* image, int32_t& e) override;
+  CFX_ByteString Decode(CBC_BinaryBitmap* image,
+                        int32_t hints,
+                        int32_t& e) override;
+
   virtual CFX_ByteString DecodeRow(int32_t rowNumber,
                                    CBC_CommonBitArray* row,
                                    int32_t hints,
-                                   int32_t& e) {
-    return "";
-  }
+                                   int32_t& e);
 
  private:
   CFX_ByteString DeDecode(CBC_BinaryBitmap* image, int32_t hints, int32_t& e);
 
  protected:
   static const int32_t INTEGER_MATH_SHIFT = 8;
   static const int32_t PATTERN_MATCH_RESULT_SCALE_FACTOR = 1 << 8;
 
   void RecordPattern(CBC_CommonBitArray* row,
                      int32_t start,
                      CFX_Int32Array* counters,
                      int32_t& e);
   void RecordPatternInReverse(CBC_CommonBitArray* row,
                               int32_t start,
                               CFX_Int32Array* counters,
                               int32_t& e);
   int32_t PatternMatchVariance(CFX_Int32Array* counters,
                                const int32_t* pattern,
                                int32_t maxIndividualVariance);
 };
 
 #endif  // XFA_FXBARCODE_ONED_BC_ONEDREADER_H_