Cleanup unused methods and return values in FWL code.

xfa/fwl/theme/cfwl_checkboxtp.h

Index: xfa/fwl/theme/cfwl_checkboxtp.h
diff --git a/xfa/fwl/theme/cfwl_checkboxtp.h b/xfa/fwl/theme/cfwl_checkboxtp.h
index cdc4ba1d57335331d1aa169b23f0cb049cd89cff..37a8686170525c5a201fa3444f27d32650c73610 100644
--- a/xfa/fwl/theme/cfwl_checkboxtp.h
+++ b/xfa/fwl/theme/cfwl_checkboxtp.h
@@ -18,12 +18,12 @@ class CFWL_CheckBoxTP : public CFWL_WidgetTP {
   ~CFWL_CheckBoxTP() override;
 
   // CFWL_WidgeTP
+  void Initialize() override;
+  void Finalize() override;
   bool IsValidWidget(IFWL_Widget* pWidget) override;
   uint32_t SetThemeID(IFWL_Widget* pWidget, uint32_t dwThemeID) override;
-  FX_BOOL DrawText(CFWL_ThemeText* pParams) override;
-  FX_BOOL DrawBackground(CFWL_ThemeBackground* pParams) override;
-  FWL_Error Initialize() override;
-  FWL_Error Finalize() override;
+  void DrawText(CFWL_ThemeText* pParams) override;
+  void DrawBackground(CFWL_ThemeBackground* pParams) override;
 
  protected:
   struct CKBThemeData {