Cleanup IFWL_Widget visibility and virtual parameters

xfa/fwl/core/ifwl_scrollbar.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_CORE_IFWL_SCROLLBAR_H_
 #define XFA_FWL_CORE_IFWL_SCROLLBAR_H_
 
 #include "core/fxcrt/fx_system.h"
@@ skipping 25 matching lines @@
 
 class IFWL_ScrollBar : public IFWL_Widget {
  public:
   IFWL_ScrollBar(const IFWL_App* app,
                  std::unique_ptr<CFWL_WidgetProperties> properties,
                  IFWL_Widget* pOuter);
   ~IFWL_ScrollBar() override;
 
   // IFWL_Widget
   FWL_Type GetClassID() const override;
-  FWL_Error GetWidgetRect(CFX_RectF& rect, bool bAutoSize = false) override;
-  FWL_Error Update() override;
-  FWL_Error DrawWidget(CFX_Graphics* pGraphics,
-                       const CFX_Matrix* pMatrix = nullptr) override;
+  void GetWidgetRect(CFX_RectF& rect, bool bAutoSize = false) override;
+  void Update() override;
+  void DrawWidget(CFX_Graphics* pGraphics,
+                  const CFX_Matrix* pMatrix = nullptr) override;
   void OnProcessMessage(CFWL_Message* pMessage) override;
   void OnDrawWidget(CFX_Graphics* pGraphics,
                     const CFX_Matrix* pMatrix) override;
 
   bool IsVertical();
   FWL_Error GetRange(FX_FLOAT& fMin, FX_FLOAT& fMax);
   FWL_Error SetRange(FX_FLOAT fMin, FX_FLOAT fMax);
   FX_FLOAT GetPageSize();
   FWL_Error SetPageSize(FX_FLOAT fPageSize);
   FX_FLOAT GetStepSize();
@@ skipping 94 matching lines @@
   void DoMouseMove(int32_t iItem,
                    const CFX_RectF& rtItem,
                    int32_t& iState,
                    FX_FLOAT fx,
                    FX_FLOAT fy);
   void DoMouseLeave(int32_t iItem, const CFX_RectF& rtItem, int32_t& iState);
   void DoMouseHover(int32_t iItem, const CFX_RectF& rtItem, int32_t& iState);
 };
 
 #endif  // XFA_FWL_CORE_IFWL_SCROLLBAR_H_