Use override in more classes in fpdfsdk/

fpdfsdk/include/pdfwindow/PWL_Signature.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef FPDFSDK_INCLUDE_PDFWINDOW_PWL_SIGNATURE_H_
 #define FPDFSDK_INCLUDE_PDFWINDOW_PWL_SIGNATURE_H_
 
 #include "PWL_Icon.h"
 #include "PWL_Wnd.h"
 
 class CFX_DIBSource;
 class CPWL_Label;
 
 class CPWL_Signature_Image : public CPWL_Image {
  public:
   CPWL_Signature_Image();
-  virtual ~CPWL_Signature_Image();
+  ~CPWL_Signature_Image() override;
 
   void SetImage(CFX_DIBSource* pImage);
   CFX_DIBSource* GetImage();
 
  protected:
-  virtual void DrawThisAppearance(CFX_RenderDevice* pDevice,
-                                  CPDF_Matrix* pUser2Device);
-  virtual void GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream);
-
-  virtual void GetScale(FX_FLOAT& fHScale, FX_FLOAT& fVScale);
+  // CPWL_Image
+  void DrawThisAppearance(CFX_RenderDevice* pDevice,
+                          CPDF_Matrix* pUser2Device) override;
+  void GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) override;
+  void GetScale(FX_FLOAT& fHScale, FX_FLOAT& fVScale) override;
 
  private:
   CFX_DIBSource* m_pImage;
 };
 
 class CPWL_Signature : public CPWL_Wnd {
  public:
   CPWL_Signature();
-  virtual ~CPWL_Signature();
+  ~CPWL_Signature() override;
 
   void SetText(const FX_WCHAR* sText);
   void SetDescription(const FX_WCHAR* string);
   void SetImage(CFX_DIBSource* pImage);
   void SetImageStream(CPDF_Stream* pStream, const FX_CHAR* sImageAlias);
 
   void SetTextFlag(FX_BOOL bTextExist);
   void SetImageFlag(FX_BOOL bImageExist);
   void SetFoxitFlag(FX_BOOL bFlagExist);
 
  protected:
-  virtual void RePosChildWnd();
-  virtual void CreateChildWnd(const PWL_CREATEPARAM& cp);
-
-  virtual void DrawThisAppearance(CFX_RenderDevice* pDevice,
-                                  CPDF_Matrix* pUser2Device);
-  virtual void GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream);
+  // CPWL_Wnd
+  void RePosChildWnd() override;
+  void CreateChildWnd(const PWL_CREATEPARAM& cp) override;
+  void DrawThisAppearance(CFX_RenderDevice* pDevice,
+                          CPDF_Matrix* pUser2Device) override;
+  void GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) override;
 
  private:
   CPWL_Label* m_pText;
   CPWL_Label* m_pDescription;
   CPWL_Signature_Image* m_pImage;
 
   FX_BOOL m_bTextExist;
   FX_BOOL m_bImageExist;
   FX_BOOL m_bFlagExist;
 };
 
 #endif  // FPDFSDK_INCLUDE_PDFWINDOW_PWL_SIGNATURE_H_