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

ios/chrome/browser/web/BUILD.gn

Index: ios/chrome/browser/web/BUILD.gn
diff --git a/ios/chrome/browser/web/BUILD.gn b/ios/chrome/browser/web/BUILD.gn
index eadf4a51b956e100fec79dd8794b1720db4478fb..e6b87283a5c7a118c22565dd23ca7fe370694b7e 100644
--- a/ios/chrome/browser/web/BUILD.gn
+++ b/ios/chrome/browser/web/BUILD.gn
@@ -181,9 +181,18 @@ js_compile_bundle("chrome_bundle") {
   closure_entry_point = "__crWeb.chromeBundle"
   sources = [
     "resources/chrome_bundle.js",
-    "resources/payment_request.js",
     "resources/print.js",
   ]
+
+  deps = [
+    ":payment_request",
+  ]
+}
+
+js_compile_unchecked("payment_request") {
+  sources = [
+    "resources/payment_request.js",
+  ]
 }
 
 source_set("web_internal") {
@@ -281,6 +290,7 @@ source_set("unit_tests_internal") {
     "//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",