Make CBC_CodeBase::SetTextLocation() virtual.

Do the same for a few other CBC_CodeBase methods, instead of trying to
implement virtual methods manually using memory pointers.

Change-Id: Iec0e3a4f8eabc54962c7ac0a00a1b80b192ff474
Reviewed-on: https://pdfium-review.googlesource.com/42600
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/fxbarcode/cbc_codabar.h b/fxbarcode/cbc_codabar.h
index 036c65f..7fc518b 100644
--- a/fxbarcode/cbc_codabar.h
+++ b/fxbarcode/cbc_codabar.h
@@ -20,15 +20,14 @@
   ~CBC_Codabar() override;
 
   // CBC_OneCode:
+  BC_TYPE GetType() override;
   bool Encode(const WideStringView& contents) override;
   bool RenderDevice(CFX_RenderDevice* device,
                     const CFX_Matrix* matrix) override;
-  BC_TYPE GetType() override;
-
-  bool SetStartChar(char start);
-  bool SetEndChar(char end);
-  bool SetTextLocation(BC_TEXT_LOC location);
-  bool SetWideNarrowRatio(int8_t ratio);
+  bool SetTextLocation(BC_TEXT_LOC location) override;
+  bool SetWideNarrowRatio(int8_t ratio) override;
+  bool SetStartChar(char start) override;
+  bool SetEndChar(char end) override;
 
  private:
   CBC_OnedCodaBarWriter* GetOnedCodaBarWriter();