Unify CFWL_WidgetProperties and CFWL_WidgetImpProperties.

xfa/fwl/core/cfwl_combobox.cpp

Index: xfa/fwl/core/cfwl_combobox.cpp
diff --git a/xfa/fwl/core/cfwl_combobox.cpp b/xfa/fwl/core/cfwl_combobox.cpp
index e8dde06039ed0b07b6ae5dcc2e16c0609158b6ab..60b6e507d13f0ad10d3a764917c0f0570bead5c9 100644
--- a/xfa/fwl/core/cfwl_combobox.cpp
+++ b/xfa/fwl/core/cfwl_combobox.cpp
@@ -32,7 +32,7 @@ void CFWL_ComboBox::Initialize() {
   ASSERT(!m_pIface);
 
   m_pIface = pdfium::MakeUnique<IFWL_ComboBox>(
-      m_pApp, m_pProperties->MakeWidgetImpProperties(&m_comboBoxData));
+      m_pApp, pdfium::MakeUnique<CFWL_WidgetProperties>(&m_comboBoxData));
 
   CFWL_Widget::Initialize();
 }