Convert FWL_ERR into an enum class.

xfa/fwl/core/ifwl_form.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_FORM_H_
 #define XFA_FWL_CORE_IFWL_FORM_H_
 
 #include "xfa/fwl/core/ifwl_dataprovider.h"
@@ skipping 35 matching lines @@
   virtual CFX_DIBitmap* GetIcon(IFWL_Widget* pWidget, FX_BOOL bBig) = 0;
 };
 
 class IFWL_Form : public IFWL_Widget {
  public:
   static IFWL_Form* CreateFormProxy(CFWL_WidgetImpProperties& properties,
                                     CFX_WideString* classname,
                                     IFWL_Widget* pOuter);
 
   FWL_FORMSIZE GetFormSize();
-  FWL_ERR SetFormSize(FWL_FORMSIZE eFormSize);
+  FWL_Error SetFormSize(FWL_FORMSIZE eFormSize);
   IFWL_Widget* DoModal();
   IFWL_Widget* DoModal(uint32_t& dwCommandID);
-  FWL_ERR EndDoModal();
-  FWL_ERR SetBorderRegion(CFX_Path* pPath);
+  FWL_Error EndDoModal();
+  FWL_Error SetBorderRegion(CFX_Path* pPath);
 
  protected:
   IFWL_Form();
 };
 
 #endif  // XFA_FWL_CORE_IFWL_FORM_H_