Restructure EAN barcode classes to merge common code.

Add an additional layer of class hierarchy to merge some common code
between 3 very similar barcode implementations.

Change-Id: I435613006a59b1af8c7d05e7c8ba50f64a2c43b5
Reviewed-on: https://pdfium-review.googlesource.com/c/46150
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/fxbarcode/cbc_onecode.h b/fxbarcode/cbc_onecode.h
index eae618e..946911c 100644
--- a/fxbarcode/cbc_onecode.h
+++ b/fxbarcode/cbc_onecode.h
@@ -24,13 +24,13 @@
   virtual bool CheckContentValidity(const WideStringView& contents);
   virtual WideString FilterContents(const WideStringView& contents);
 
-  virtual void SetPrintChecksum(bool checksum);
-  virtual void SetDataLength(int32_t length);
-  virtual void SetCalChecksum(bool calc);
-  virtual bool SetFont(CFX_Font* cFont);
-  virtual void SetFontSize(float size);
-  virtual void SetFontStyle(int32_t style);
-  virtual void SetFontColor(FX_ARGB color);
+  void SetPrintChecksum(bool checksum);
+  void SetDataLength(int32_t length);
+  void SetCalChecksum(bool calc);
+  bool SetFont(CFX_Font* cFont);
+  void SetFontSize(float size);
+  void SetFontStyle(int32_t style);
+  void SetFontColor(FX_ARGB color);
 
  private:
   CBC_OneDimWriter* GetOneDimWriter();