Split fwl/core class pt I.

xfa/fwl/core/cfwl_picturebox.h

Index: xfa/fwl/core/cfwl_picturebox.h
diff --git a/xfa/fwl/core/cfwl_picturebox.h b/xfa/fwl/core/cfwl_picturebox.h
index 12a8b632ff380ab1d75a3974060c274790538a69..d1be78bda44614cb20070321592dddfe80f34e56 100644
--- a/xfa/fwl/core/cfwl_picturebox.h
+++ b/xfa/fwl/core/cfwl_picturebox.h
@@ -9,15 +9,16 @@
 
 #include "xfa/fwl/core/cfwl_widget.h"
 #include "xfa/fwl/core/ifwl_picturebox.h"
+#include "xfa/fwl/core/ifwl_widget.h"
 
-class CFWL_PictureBox : public CFWL_Widget, public IFWL_PictureBoxDP {
+class CFWL_PictureBox : public CFWL_Widget, public IFWL_Widget::DataProvider {
  public:
   explicit CFWL_PictureBox(const IFWL_App* pApp);
   ~CFWL_PictureBox() override;
 
   void Initialize();
 
-  // IFWL_DataProvider
+  // IFWL_Widget::DataProvider
   void GetCaption(IFWL_Widget* pWidget, CFX_WideString& wsCaption) override;
 };