Several pure virtual IFWL_Adapter* classes not implemented.

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build_overrides/v8.gni")
 import("//testing/test.gni")
 import("pdfium.gni")
 
 config("pdfium_config") {
   cflags = []
@@ skipping 758 matching lines @@
     deps = [
       ":xfa",
     ]
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [ ":pdfium_config", "//build/config/compiler:no_chromium_code" ]
   }
 
   static_library("xfa") {
     sources = [
       "xfa/include/foxitxfa.h",
-      "xfa/include/fwl/adapter/fwl_adapterclipboardmgr.h",
-      "xfa/include/fwl/adapter/fwl_adaptercursormgr.h",
-      "xfa/include/fwl/adapter/fwl_adaptermonitormgr.h",
       "xfa/include/fwl/adapter/fwl_adapternative.h",
       "xfa/include/fwl/adapter/fwl_adapterthreadmgr.h",
       "xfa/include/fwl/adapter/fwl_adaptertimermgr.h",
       "xfa/include/fwl/adapter/fwl_adapterwidgetmgr.h",
       "xfa/include/fwl/adapter/fwl_sdadapterimp.h",
       "xfa/include/fwl/basewidget/fwl_barcode.h",
       "xfa/include/fwl/basewidget/fwl_caret.h",
       "xfa/include/fwl/basewidget/fwl_checkbox.h",
       "xfa/include/fwl/basewidget/fwl_combobox.h",
       "xfa/include/fwl/basewidget/fwl_datetimepicker.h",
@@ skipping 727 matching lines @@
       "//v8:v8_libplatform",
     ]
     include_dirs += [
       "//v8",
       "//v8/include",
     ]
     configs += [ "//v8:external_startup_data" ]
   }
   configs += [ ":pdfium_config" ]
 }