Move xfa/include/fwl/{core,basewidget} to xfa/fwl/{core,basewidget}.

xfa/fwl/core/ifwl_custom.h

+// Copyright 2016 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#ifndef XFA_FWL_CORE_IFWL_CUSTOM_H_
+#define XFA_FWL_CORE_IFWL_CUSTOM_H_
+
+#include "xfa/fwl/core/fwl_error.h"
+#include "xfa/fwl/core/ifwl_widget.h"
+
+class IFWL_Proxy;
+
+class IFWL_Custom : public IFWL_Widget {
+ public:
+  static IFWL_Custom* Create(const CFWL_WidgetImpProperties& properties,
+                             IFWL_Widget* pOuter);
+
+  FWL_ERR SetProxy(IFWL_Proxy* pProxy);
+
+ protected:
+  IFWL_Custom();
+};
+
+#endif  // XFA_FWL_CORE_IFWL_CUSTOM_H_