[Payments] Cache payment manifests.

components/payments/android/BUILD.gn

 # Copyright 2017 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.
 
 static_library("android") {
   sources = [
+    "payment_manifest_web_data_service.cc",
+    "payment_manifest_web_data_service.h",
     "payment_method_manifest_table.cc",
     "payment_method_manifest_table.h",
     "web_app_manifest_section_table.cc",
     "web_app_manifest_section_table.h",
   ]
 
   deps = [
     "//components/payments/mojom:mojom_parser",
     "//components/webdata/common",
     "//sql",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "payment_method_manifest_table_unittest.cc",
     "web_app_manifest_section_table_unittest.cc",
   ]
 
   deps = [
     ":android",
     "//base",
     "//testing/gtest",
   ]
 }