Remove header files that only have includes.

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 214 matching lines @@
 static_library("fpdfapi") {
   sources = [
     "core/include/fpdfapi/fpdf_module.h",
     "core/include/fpdfapi/fpdf_objects.h",
     "core/include/fpdfapi/fpdf_page.h",
     "core/include/fpdfapi/fpdf_pageobj.h",
     "core/include/fpdfapi/fpdf_parser.h",
     "core/include/fpdfapi/fpdf_render.h",
     "core/include/fpdfapi/fpdf_resource.h",
     "core/include/fpdfapi/fpdf_serial.h",
-    "core/include/fpdfapi/fpdfapi.h",
     "core/src/fpdfapi/fpdf_basic_module.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/Adobe-CNS1-UCS2_5.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/B5pc-H_0.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/B5pc-V_0.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/CNS-EUC-H_0.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/CNS-EUC-V_0.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/ETen-B5-H_0.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/ETen-B5-V_0.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/ETenms-B5-H_0.cpp",
     "core/src/fpdfapi/fpdf_cmaps/CNS1/ETenms-B5-V_0.cpp",
@@ skipping 330 matching lines @@
     ]
     configs -= [ "//build/config/win:lean_and_mean" ]
   }
 }
 
 static_library("fxedit") {
   sources = [
     "fpdfsdk/include/fxedit/fx_edit.h",
     "fpdfsdk/include/fxedit/fxet_edit.h",
     "fpdfsdk/include/fxedit/fxet_list.h",
-    "fpdfsdk/include/fxedit/fxet_stub.h",
     "fpdfsdk/src/fxedit/fxet_ap.cpp",
     "fpdfsdk/src/fxedit/fxet_edit.cpp",
     "fpdfsdk/src/fxedit/fxet_list.cpp",
     "fpdfsdk/src/fxedit/fxet_module.cpp",
     "fpdfsdk/src/fxedit/fxet_pageobjs.cpp",
   ]
   configs += [ ":pdfium_config" ]
 }
 
 static_library("pdfwindow") {
   sources = [
-    "fpdfsdk/include/pdfwindow/IPDFWindow.h",
-    "fpdfsdk/include/pdfwindow/PDFWindow.h",
     "fpdfsdk/include/pdfwindow/PWL_Button.h",
     "fpdfsdk/include/pdfwindow/PWL_Caret.h",
     "fpdfsdk/include/pdfwindow/PWL_ComboBox.h",
     "fpdfsdk/include/pdfwindow/PWL_Edit.h",
     "fpdfsdk/include/pdfwindow/PWL_EditCtrl.h",
     "fpdfsdk/include/pdfwindow/PWL_FontMap.h",
     "fpdfsdk/include/pdfwindow/PWL_Icon.h",
     "fpdfsdk/include/pdfwindow/PWL_IconList.h",
     "fpdfsdk/include/pdfwindow/PWL_Label.h",
     "fpdfsdk/include/pdfwindow/PWL_ListBox.h",
@@ skipping 91 matching lines @@
   sources = [
     "fpdfsdk/include/formfiller/FFL_CBA_Fontmap.h",
     "fpdfsdk/include/formfiller/FFL_CheckBox.h",
     "fpdfsdk/include/formfiller/FFL_ComboBox.h",
     "fpdfsdk/include/formfiller/FFL_FormFiller.h",
     "fpdfsdk/include/formfiller/FFL_IFormFiller.h",
     "fpdfsdk/include/formfiller/FFL_ListBox.h",
     "fpdfsdk/include/formfiller/FFL_PushButton.h",
     "fpdfsdk/include/formfiller/FFL_RadioButton.h",
     "fpdfsdk/include/formfiller/FFL_TextField.h",
-    "fpdfsdk/include/formfiller/FormFiller.h",
     "fpdfsdk/src/formfiller/FFL_CBA_Fontmap.cpp",
     "fpdfsdk/src/formfiller/FFL_CheckBox.cpp",
     "fpdfsdk/src/formfiller/FFL_ComboBox.cpp",
     "fpdfsdk/src/formfiller/FFL_FormFiller.cpp",
     "fpdfsdk/src/formfiller/FFL_IFormFiller.cpp",
     "fpdfsdk/src/formfiller/FFL_ListBox.cpp",
     "fpdfsdk/src/formfiller/FFL_PushButton.cpp",
     "fpdfsdk/src/formfiller/FFL_RadioButton.cpp",
     "fpdfsdk/src/formfiller/FFL_TextField.cpp",
   ]
@@ skipping 65 matching lines @@
       "//v8:v8_libplatform",
     ]
     include_dirs += [
       "//v8",
       "//v8/include",
     ]
     configs += [ "//v8:external_startup_data" ]
   }
   configs += [ ":pdfium_config" ]
 }