Cleanup remaining IFWL files for visiblity and usage.

xfa/fwl/core/cfwl_checkbox.cpp

Index: xfa/fwl/core/cfwl_checkbox.cpp
diff --git a/xfa/fwl/core/cfwl_checkbox.cpp b/xfa/fwl/core/cfwl_checkbox.cpp
index 75e85fcabb993aa970cd97579d4ff849c7ef9d03..08371fca4a42242118c925289bf08a5390a6484e 100644
--- a/xfa/fwl/core/cfwl_checkbox.cpp
+++ b/xfa/fwl/core/cfwl_checkbox.cpp
@@ -11,14 +11,6 @@
 #include "third_party/base/ptr_util.h"
 #include "xfa/fwl/core/fwl_error.h"
 
-namespace {
-
-IFWL_CheckBox* ToCheckBox(IFWL_Widget* widget) {
-  return static_cast<IFWL_CheckBox*>(widget);
-}
-
-}  // namespace
-
 CFWL_CheckBox::CFWL_CheckBox(const IFWL_App* app)
     : CFWL_Widget(app), m_fBoxHeight(16.0f), m_wsCaption(L"Check box") {}
 
@@ -33,22 +25,8 @@ void CFWL_CheckBox::Initialize() {
   CFWL_Widget::Initialize();
 }
 
-FWL_Error CFWL_CheckBox::SetCaption(const CFX_WideStringC& wsCaption) {
-  m_wsCaption = wsCaption;
-  return FWL_Error::Succeeded;
-}
-
-FWL_Error CFWL_CheckBox::SetBoxSize(FX_FLOAT fHeight) {
+void CFWL_CheckBox::SetBoxSize(FX_FLOAT fHeight) {
   m_fBoxHeight = fHeight;
-  return FWL_Error::Succeeded;
-}
-
-int32_t CFWL_CheckBox::GetCheckState() {
-  return ToCheckBox(GetWidget())->GetCheckState();
-}
-
-FWL_Error CFWL_CheckBox::SetCheckState(int32_t iCheck) {
-  return ToCheckBox(GetWidget())->SetCheckState(iCheck);
 }
 
 void CFWL_CheckBox::GetCaption(IFWL_Widget* pWidget,