Remove CLASSHASH defines in favour of an enum class.

xfa/fwl/theme/cfwl_scrollbartp.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 XFA_FWL_THEME_CFWL_SCROLLBARTP_H_
 #define XFA_FWL_THEME_CFWL_SCROLLBARTP_H_
 
 #include "xfa/fwl/theme/cfwl_widgettp.h"
 
 class CFWL_ScrollBarTP : public CFWL_WidgetTP {
  public:
   CFWL_ScrollBarTP();
-  virtual ~CFWL_ScrollBarTP();
-  virtual FX_BOOL IsValidWidget(IFWL_Widget* pWidget);
-  virtual uint32_t SetThemeID(IFWL_Widget* pWidget,
-                              uint32_t dwThemeID,
-                              FX_BOOL bChildren = TRUE);
-  virtual FX_BOOL DrawBackground(CFWL_ThemeBackground* pParams);
-  virtual void* GetCapacity(CFWL_ThemePart* pThemePart,
-                            CFWL_WidgetCapacity dwCapacity);
+  ~CFWL_ScrollBarTP() override;
+
+  // CFWL_WidgetTP
+  bool IsValidWidget(IFWL_Widget* pWidget) override;
+  uint32_t SetThemeID(IFWL_Widget* pWidget,
+                      uint32_t dwThemeID,
+                      FX_BOOL bChildren = TRUE) override;
+  FX_BOOL DrawBackground(CFWL_ThemeBackground* pParams) override;
+  void* GetCapacity(CFWL_ThemePart* pThemePart,
+                    CFWL_WidgetCapacity dwCapacity) override;
 
  protected:
   struct SBThemeData {
     FX_ARGB clrPawColorLight[4];
     FX_ARGB clrPawColorDark[4];
     FX_ARGB clrBtnBK[4][2];
     FX_ARGB clrBtnBorder[4];
     FX_ARGB clrTrackBKStart;
     FX_ARGB clrTrackBKEnd;
   };
@@ skipping 19 matching lines @@
                const CFX_RectF* pRect,
                FX_BOOL bVert,
                FWLTHEME_STATE eState,
                CFX_Matrix* pMatrix = NULL);
   void SetThemeData(uint32_t dwID);
 
   struct SBThemeData* m_pThemeData;
 };
 
 #endif  // XFA_FWL_THEME_CFWL_SCROLLBARTP_H_