Make code compile with clang_use_chrome_plugin (part III)

This change contains files in xfa/fxbarcode directory.
This is part of the efforts to make PDFium code compilable
by Clang chromium style plugins.

The changes are mainly the following:
-- move inline constructor/destructor of complex class/struct out-of-line;
-- add constructor/destructor of complex class/struct if not
 explicitly defined;
-- add explicit out-of-line copy constructor when needed;
-- move inline virtual functions out-of-line;
-- Properly mark virtual functions with 'override';
-- some minor cleanups;

BUG=pdfium:469

Review-Url: https://codereview.chromium.org/2067903002

1 files changed, 5 insertions, 3 deletions

diff --git a/xfa/fxbarcode/datamatrix/BC_Base256Encoder.h b/xfa/fxbarcode/datamatrix/BC_Base256Encoder.h
index 64dbdc7ba4..c41c79db08 100644
--- a/xfa/fxbarcode/datamatrix/BC_Base256Encoder.h
+++ b/xfa/fxbarcode/datamatrix/BC_Base256Encoder.h
@@ -12,9 +12,11 @@
 class CBC_Base256Encoder : public CBC_Encoder {
  public:
   CBC_Base256Encoder();
-  virtual ~CBC_Base256Encoder();
-  int32_t getEncodingMode();
-  void Encode(CBC_EncoderContext& context, int32_t& e);
+  ~CBC_Base256Encoder() override;
+
+  // CBC_Encoder
+  int32_t getEncodingMode() override;
+  void Encode(CBC_EncoderContext& context, int32_t& e) override;
 
  private:
   static FX_WCHAR randomize255State(FX_WCHAR ch, int32_t codewordPosition);