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, 9 insertions, 6 deletions

diff --git a/xfa/fxbarcode/datamatrix/BC_DataMatrixWriter.h b/xfa/fxbarcode/datamatrix/BC_DataMatrixWriter.h
index 7c19a07c19..1196e46352 100644
--- a/xfa/fxbarcode/datamatrix/BC_DataMatrixWriter.h
+++ b/xfa/fxbarcode/datamatrix/BC_DataMatrixWriter.h
@@ -16,12 +16,15 @@ class CBC_SymbolInfo;
 class CBC_DataMatrixWriter : public CBC_TwoDimWriter {
  public:
   CBC_DataMatrixWriter();
-  virtual ~CBC_DataMatrixWriter();
-  uint8_t* Encode(const CFX_WideString& contents,
-                  int32_t& outWidth,
-                  int32_t& outHeight,
-                  int32_t& e);
-  FX_BOOL SetErrorCorrectionLevel(int32_t level);
+  ~CBC_DataMatrixWriter() override;
+
+  virtual uint8_t* Encode(const CFX_WideString& contents,
+                          int32_t& outWidth,
+                          int32_t& outHeight,
+                          int32_t& e);
+
+  // CBC_TwoDimWriter
+  FX_BOOL SetErrorCorrectionLevel(int32_t level) override;
 
  private:
   static CBC_CommonByteMatrix* encodeLowLevel(CBC_DefaultPlacement* placement,