Remove CLASSHASH defines in favour of an enum class.

xfa/fwl/theme/cfwl_datetimepickertp.h

Index: xfa/fwl/theme/cfwl_datetimepickertp.h
diff --git a/xfa/fwl/theme/cfwl_datetimepickertp.h b/xfa/fwl/theme/cfwl_datetimepickertp.h
index 199551ea1faba8ac69364fd3c06966fedcf11778..1b8899b73ec341ad4f7726890588d0ec9b546954 100644
--- a/xfa/fwl/theme/cfwl_datetimepickertp.h
+++ b/xfa/fwl/theme/cfwl_datetimepickertp.h
@@ -12,13 +12,16 @@
 class CFWL_DateTimePickerTP : public CFWL_WidgetTP {
  public:
   CFWL_DateTimePickerTP();
-  virtual ~CFWL_DateTimePickerTP();
-  virtual FX_BOOL IsValidWidget(IFWL_Widget* pWidget);
-  virtual FX_BOOL DrawBackground(CFWL_ThemeBackground* pParams);
+  ~CFWL_DateTimePickerTP() override;
+
+  // CFWL_WidgetTP
+  bool IsValidWidget(IFWL_Widget* pWidget) override;
+  FX_BOOL DrawBackground(CFWL_ThemeBackground* pParams) override;
 
  protected:
   void DrawDropDownButton(CFWL_ThemeBackground* pParams, CFX_Matrix* pMatrix);
   void initThemeData();
+
   struct DTPThemeData {
     FX_ARGB BoxBkColor[13][2];
   } * m_pThemeData;