Merge IFWL and CFWL classes.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index d099be17bd5a1e5b9d150e03d234fdd39f3e8ff8..b61fa32e6302f57bfcdcfdd05eec920cb64e67e3 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1300,25 +1300,7 @@ if (pdf_enable_xfa) {
       "xfa/fwl/core/fwl_widgetdef.h",
       "xfa/fwl/core/fwl_widgethit.h",
       "xfa/fwl/core/ifwl_adaptertimermgr.h",
-      "xfa/fwl/core/ifwl_barcode.cpp",
-      "xfa/fwl/core/ifwl_barcode.h",
-      "xfa/fwl/core/ifwl_checkbox.cpp",
-      "xfa/fwl/core/ifwl_checkbox.h",
-      "xfa/fwl/core/ifwl_combobox.cpp",
-      "xfa/fwl/core/ifwl_combobox.h",
-      "xfa/fwl/core/ifwl_datetimepicker.cpp",
-      "xfa/fwl/core/ifwl_datetimepicker.h",
-      "xfa/fwl/core/ifwl_edit.cpp",
-      "xfa/fwl/core/ifwl_edit.h",
-      "xfa/fwl/core/ifwl_listbox.cpp",
-      "xfa/fwl/core/ifwl_listbox.h",
-      "xfa/fwl/core/ifwl_picturebox.cpp",
-      "xfa/fwl/core/ifwl_picturebox.h",
-      "xfa/fwl/core/ifwl_pushbutton.cpp",
-      "xfa/fwl/core/ifwl_pushbutton.h",
       "xfa/fwl/core/ifwl_themeprovider.h",
-      "xfa/fwl/core/ifwl_widget.cpp",
-      "xfa/fwl/core/ifwl_widget.h",
       "xfa/fwl/core/ifwl_widgetdelegate.h",
       "xfa/fwl/core/ifwl_widgetmgrdelegate.h",
       "xfa/fwl/theme/cfwl_arrowdata.cpp",