[Payment Request] window.PaymentRequest must be undefined if PR is disabled

ios/chrome/browser/web/BUILD.gn

 # Copyright 2016 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("//ios/web/js_compile.gni")
 
 source_set("web") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "dom_altering_lock.h",
@@ skipping 162 matching lines @@
   ]
   outputs = [
     "{{bundle_resources_dir}}/{{source_file_part}}",
   ]
 }
 
 js_compile_bundle("chrome_bundle") {
   closure_entry_point = "__crWeb.chromeBundle"
   sources = [
     "resources/chrome_bundle.js",
+    "resources/print.js",
+  ]
+
+  deps = [
+    ":payment_request",
+  ]
+}
+
+js_compile_unchecked("payment_request") {
+  sources = [
     "resources/payment_request.js",
-    "resources/print.js",
   ]
 }
 
 source_set("web_internal") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "auto_reload_bridge.h",
     "auto_reload_bridge.mm",
     "auto_reload_controller.h",
     "auto_reload_controller.mm",
@@ skipping 78 matching lines @@
     "error_page_generator_unittest.mm",
     "external_app_launcher_unittest.mm",
   ]
   deps = [
     ":test_support",
     ":web_internal",
     "//base",
     "//base/test:test_support",
     "//components/content_settings/core/browser",
     "//components/infobars/core",
+    "//ios/chrome/browser",
     "//ios/chrome/browser/browser_state:test_support",
     "//ios/chrome/browser/content_settings:content_settings",
     "//ios/chrome/browser/find_in_page",
     "//ios/chrome/browser/infobars",
     "//ios/chrome/browser/ui",
     "//ios/web",
     "//ios/web:test_support",
     "//net",
     "//testing/gtest",
     "//third_party/ocmock",
@@ skipping 57 matching lines @@
     "early_page_script_perftest.mm",
   ]
   deps = [
     "//base",
     "//ios/chrome/test/base:perf_test_support",
     "//ios/web",
     "//ios/web:test_support",
   ]
   libs = [ "WebKit.framework" ]
 }