Kill dead IFWL_*::Initialize() variants dead.

xfa/include/fwl/basewidget/fwl_checkbox.h

Index: xfa/include/fwl/basewidget/fwl_checkbox.h
diff --git a/xfa/include/fwl/basewidget/fwl_checkbox.h b/xfa/include/fwl/basewidget/fwl_checkbox.h
index 63cc75896ab557f8e2f5bcf29bffe9e51187a932..989430acc19261a1626ba079e411d94b0fdb47c1 100644
--- a/xfa/include/fwl/basewidget/fwl_checkbox.h
+++ b/xfa/include/fwl/basewidget/fwl_checkbox.h
@@ -71,9 +71,8 @@ class IFWL_CheckBoxDP : public IFWL_DataProvider {
 class IFWL_CheckBox : public IFWL_Widget {
  public:
   static IFWL_CheckBox* Create();
-  FWL_ERR Initialize(IFWL_Widget* pOuter = NULL);
   FWL_ERR Initialize(const CFWL_WidgetImpProperties& properties,
-                     IFWL_Widget* pOuter = NULL);
+                     IFWL_Widget* pOuter);
   int32_t GetCheckState();
   FWL_ERR SetCheckState(int32_t iCheck);
 
@@ -83,9 +82,8 @@ class IFWL_CheckBox : public IFWL_Widget {
 class IFWL_RadioButton : public IFWL_Widget {
  public:
   static IFWL_RadioButton* Create();
-  FWL_ERR Initialize(IFWL_Widget* pOuter = NULL);
   FWL_ERR Initialize(const CFWL_WidgetImpProperties& properties,
-                     IFWL_Widget* pOuter = NULL);
+                     IFWL_Widget* pOuter);
   int32_t GetCheckState();
   FWL_ERR SetCheckState(int32_t iCheck);