Convert FWL_ERR into an enum class.

xfa/fwl/basewidget/ifwl_caret.h

Index: xfa/fwl/basewidget/ifwl_caret.h
diff --git a/xfa/fwl/basewidget/ifwl_caret.h b/xfa/fwl/basewidget/ifwl_caret.h
index 08a98c91c470a482e3c1989912ed194bfae5ede8..5f068355960f8b236d16a5d0c7b7618666517c4e 100644
--- a/xfa/fwl/basewidget/ifwl_caret.h
+++ b/xfa/fwl/basewidget/ifwl_caret.h
@@ -19,10 +19,10 @@ class IFWL_Caret : public IFWL_Widget {
   static IFWL_Caret* Create(const CFWL_WidgetImpProperties& properties,
                             IFWL_Widget* pOuter);
 
-  FWL_ERR ShowCaret(FX_BOOL bFlag = TRUE);
-  FWL_ERR GetFrequency(uint32_t& elapse);
-  FWL_ERR SetFrequency(uint32_t elapse);
-  FWL_ERR SetColor(CFX_Color crFill);
+  FWL_Error ShowCaret(FX_BOOL bFlag = TRUE);
+  FWL_Error GetFrequency(uint32_t& elapse);
+  FWL_Error SetFrequency(uint32_t elapse);
+  FWL_Error SetColor(CFX_Color crFill);
 
  protected:
   IFWL_Caret();