Use override in more classes in fpdfsdk/

fpdfsdk/include/pdfwindow/PWL_Label.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_LABEL_H_
 #define FPDFSDK_INCLUDE_PDFWINDOW_PWL_LABEL_H_
 
 #include "PWL_Wnd.h"
 
 class IFX_Edit;
 
 class CPWL_Label : public CPWL_Wnd {
  public:
   CPWL_Label();
-  virtual ~CPWL_Label();
-
-  virtual CFX_ByteString GetClassName() const;
-  virtual void SetFontSize(FX_FLOAT fFontSize);
-  virtual FX_FLOAT GetFontSize() const;
+  ~CPWL_Label() override;
 
   void SetText(const FX_WCHAR* csText);
   CFX_WideString GetText() const;
   void SetLimitChar(int32_t nLimitChar);
   void SetHorzScale(int32_t nHorzScale);
   void SetCharSpace(FX_FLOAT fCharSpace);
   CPDF_Rect GetContentRect() const;
   int32_t GetTotalWords();
   CFX_ByteString GetTextAppearanceStream(const CPDF_Point& ptOffset) const;
 
  protected:
-  virtual void OnCreated();
-  virtual void DrawThisAppearance(CFX_RenderDevice* pDevice,
-                                  CPDF_Matrix* pUser2Device);
-  virtual void GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream);
-  virtual void RePosChildWnd();
+  // CPWL_Wnd
+  CFX_ByteString GetClassName() const override;
+  void SetFontSize(FX_FLOAT fFontSize) override;
+  FX_FLOAT GetFontSize() const override;
+  void OnCreated() override;
+  void DrawThisAppearance(CFX_RenderDevice* pDevice,
+                          CPDF_Matrix* pUser2Device) override;
+  void GetThisAppearanceStream(CFX_ByteTextBuf& sAppStream) override;
+  void RePosChildWnd() override;
 
  private:
   void SetParamByFlag();
 
   IFX_Edit* m_pEdit;
 };
 
 #endif  // FPDFSDK_INCLUDE_PDFWINDOW_PWL_LABEL_H_