Convert FWL_ERR into an enum class.

xfa/fxfa/app/xfa_fwladapter.cpp

Index: xfa/fxfa/app/xfa_fwladapter.cpp
diff --git a/xfa/fxfa/app/xfa_fwladapter.cpp b/xfa/fxfa/app/xfa_fwladapter.cpp
index 564d479d730cc67832c8942946c32f4efd8c7ef0..4a0828b5ef9b506d0170485b5f9216056a80239b 100644
--- a/xfa/fxfa/app/xfa_fwladapter.cpp
+++ b/xfa/fxfa/app/xfa_fwladapter.cpp
@@ -13,15 +13,17 @@ CXFA_FWLAdapterWidgetMgr::CXFA_FWLAdapterWidgetMgr() {}
 
 CXFA_FWLAdapterWidgetMgr::~CXFA_FWLAdapterWidgetMgr() {}
 
-FWL_ERR CXFA_FWLAdapterWidgetMgr::RepaintWidget(IFWL_Widget* pWidget,
-                                                const CFX_RectF* pRect) {
+FWL_Error CXFA_FWLAdapterWidgetMgr::RepaintWidget(IFWL_Widget* pWidget,
+                                                  const CFX_RectF* pRect) {
   if (!pWidget)
-    return FWL_ERR_Indefinite;
+    return FWL_Error::Indefinite;
+
   CXFA_FFField* pField = (CXFA_FFField*)pWidget->GetPrivateData(pWidget);
   if (!pField)
-    return FWL_ERR_Indefinite;
+    return FWL_Error::Indefinite;
+
   pField->AddInvalidateRect(nullptr);
-  return FWL_ERR_Succeeded;
+  return FWL_Error::Succeeded;
 }
 
 FX_BOOL CXFA_FWLAdapterWidgetMgr::GetPopupPos(IFWL_Widget* pWidget,