Split fwl/core class pt I.

xfa/fwl/core/ifwl_combobox.h

Index: xfa/fwl/core/ifwl_combobox.h
diff --git a/xfa/fwl/core/ifwl_combobox.h b/xfa/fwl/core/ifwl_combobox.h
index 8e23d24de0516fc4c9fe7b8d8001123999ea1887..7cf17e2881cd4ff05bc9c14d999078af1e098009 100644
--- a/xfa/fwl/core/ifwl_combobox.h
+++ b/xfa/fwl/core/ifwl_combobox.h
@@ -45,13 +45,13 @@ class IFWL_Widget;
 #define FWL_STYLEEXT_CMB_ListItemIconText (1L << 12)
 #define FWL_STYLEEXT_CMB_ReadOnly (1L << 13)
 
-class IFWL_ComboBoxDP : public IFWL_ListBoxDP {
- public:
-  virtual FX_FLOAT GetListHeight(IFWL_Widget* pWidget) = 0;
-};
-
 class IFWL_ComboBox : public IFWL_Widget {
  public:
+  class DataProvider : public IFWL_ListBox::DataProvider {
+   public:
+    virtual FX_FLOAT GetListHeight(IFWL_Widget* pWidget) = 0;
+  };
+
   explicit IFWL_ComboBox(const IFWL_App* app,
                          std::unique_ptr<CFWL_WidgetProperties> properties);
   ~IFWL_ComboBox() override;