Cleanup various IFX_ text interfaces.

core/fpdfapi/fpdf_font/ttgsubtable.h

Index: core/fpdfapi/fpdf_font/ttgsubtable.h
diff --git a/core/fpdfapi/fpdf_font/ttgsubtable.h b/core/fpdfapi/fpdf_font/ttgsubtable.h
index 7a6c66cc2a806c3982e71a172c79fa01b5dc253d..0ef235133679d8fed4eda86b222c3fe669ed7ab8 100644
--- a/core/fpdfapi/fpdf_font/ttgsubtable.h
+++ b/core/fpdfapi/fpdf_font/ttgsubtable.h
@@ -25,6 +25,7 @@ class CFX_GlyphMap {
  protected:
   CFX_BinaryBuf m_Buffer;
 };
+
 class CFX_CTTGSUBTable {
  public:
   CFX_CTTGSUBTable(void) : m_bFeautureMapLoad(FALSE), loaded(false) {}
@@ -352,12 +353,5 @@ class CFX_CTTGSUBTable {
   struct TFeatureList FeatureList;
   struct TLookupList LookupList;
 };
-class CFX_GSUBTable final : public IFX_GSUBTable {
- public:
-  ~CFX_GSUBTable() override {}
-  FX_BOOL GetVerticalGlyph(uint32_t glyphnum, uint32_t* vglyphnum) override;
-
-  CFX_CTTGSUBTable m_GsubImp;
-};
 
 #endif  // CORE_FPDFAPI_FPDF_FONT_TTGSUBTABLE_H_