Convert FWL_ERR into an enum class.

xfa/fwl/basewidget/fwl_checkboximp.h

Index: xfa/fwl/basewidget/fwl_checkboximp.h
diff --git a/xfa/fwl/basewidget/fwl_checkboximp.h b/xfa/fwl/basewidget/fwl_checkboximp.h
index fe0ebb05cbb9f78efa44434a26c480dd95424cb3..cc5474db9a819c8c23768da70c206754b48324e2 100644
--- a/xfa/fwl/basewidget/fwl_checkboximp.h
+++ b/xfa/fwl/basewidget/fwl_checkboximp.h
@@ -19,16 +19,16 @@ class CFWL_CheckBoxImp : public CFWL_WidgetImp {
   CFWL_CheckBoxImp(const CFWL_WidgetImpProperties& properties,
                    IFWL_Widget* pOuter);
   ~CFWL_CheckBoxImp();
-  virtual FWL_ERR GetClassName(CFX_WideString& wsClass) const;
+  virtual FWL_Error GetClassName(CFX_WideString& wsClass) const;
   virtual uint32_t GetClassID() const;
-  virtual FWL_ERR Initialize();
-  virtual FWL_ERR Finalize();
-  virtual FWL_ERR GetWidgetRect(CFX_RectF& rect, FX_BOOL bAutoSize = FALSE);
-  virtual FWL_ERR Update();
-  virtual FWL_ERR DrawWidget(CFX_Graphics* pGraphics,
-                             const CFX_Matrix* pMatrix = NULL);
+  virtual FWL_Error Initialize();
+  virtual FWL_Error Finalize();
+  virtual FWL_Error GetWidgetRect(CFX_RectF& rect, FX_BOOL bAutoSize = FALSE);
+  virtual FWL_Error Update();
+  virtual FWL_Error DrawWidget(CFX_Graphics* pGraphics,
+                               const CFX_Matrix* pMatrix = NULL);
   virtual int32_t GetCheckState();
-  virtual FWL_ERR SetCheckState(int32_t iCheck);
+  virtual FWL_Error SetCheckState(int32_t iCheck);
 
  protected:
   void Layout();
@@ -47,9 +47,9 @@ class CFWL_CheckBoxImp : public CFWL_WidgetImp {
 class CFWL_CheckBoxImpDelegate : public CFWL_WidgetImpDelegate {
  public:
   CFWL_CheckBoxImpDelegate(CFWL_CheckBoxImp* pOwner);
-  int32_t OnProcessMessage(CFWL_Message* pMessage) override;
-  FWL_ERR OnDrawWidget(CFX_Graphics* pGraphics,
-                       const CFX_Matrix* pMatrix = NULL) override;
+  void OnProcessMessage(CFWL_Message* pMessage) override;
+  void OnDrawWidget(CFX_Graphics* pGraphics,
+                    const CFX_Matrix* pMatrix = NULL) override;
 
  protected:
   void OnActivate(CFWL_Message* pMsg);