Remove CLASSHASH defines in favour of an enum class.

xfa/fwl/lightwidget/cfwl_widget.cpp

Index: xfa/fwl/lightwidget/cfwl_widget.cpp
diff --git a/xfa/fwl/lightwidget/cfwl_widget.cpp b/xfa/fwl/lightwidget/cfwl_widget.cpp
index e1959797b30dd0924f096359b10c26c7c7bf752c..8d3237605f858276446f488bde3ccb0a66c42261 100644
--- a/xfa/fwl/lightwidget/cfwl_widget.cpp
+++ b/xfa/fwl/lightwidget/cfwl_widget.cpp
@@ -29,9 +29,9 @@ FWL_Error CFWL_Widget::GetClassName(CFX_WideString& wsClass) const {
   return m_pIface->GetClassName(wsClass);
 }
 
-uint32_t CFWL_Widget::GetClassID() const {
+FWL_Type CFWL_Widget::GetClassID() const {
   if (!m_pIface)
-    return 0;
+    return FWL_Type::Unknown;
   return m_pIface->GetClassID();
 }