Add billing address as a mandatory field of Payments credit cards.

components/autofill/core/browser/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/config/chrome_build.gni")
 
 static_library("browser") {
   sources = [
     "address.cc",
     "address.h",
+    "address_combobox_model.cc",
+    "address_combobox_model.h",
     "address_field.cc",
     "address_field.h",
     "address_i18n.cc",
     "address_i18n.h",
     "address_rewriter.cc",
     "address_rewriter.h",
     "address_rewriter_rules.cc",
     "autocomplete_history_manager.cc",
     "autocomplete_history_manager.h",
     "autofill-inl.h",
@@ skipping 287 matching lines @@
   ]
   outputs = [
     "{{bundle_resources_dir}}/" +
         "{{source_root_relative_dir}}/{{source_file_part}}",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
+    "address_combobox_model_unittest.cc",
     "address_field_unittest.cc",
     "address_i18n_unittest.cc",
     "address_rewriter_unittest.cc",
     "address_unittest.cc",
     "autocomplete_history_manager_unittest.cc",
     "autofill_country_unittest.cc",
     "autofill_data_model_unittest.cc",
     "autofill_data_util_unittest.cc",
     "autofill_download_manager_unittest.cc",
     "autofill_driver_factory_unittest.cc",
@@ skipping 71 matching lines @@
     "//net:test_support",
     "//sql",
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/libaddressinput:util",
     "//third_party/libphonenumber",
     "//ui/base",
     "//url",
   ]
 }