PaymentHandler: Implement requestPermission().

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 1c35be896a99d9954e65326a69fdb3a19cc31904..9a100bb795d82ab7e98b20d1d61e4f9a01bfce25 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -891,6 +891,8 @@ split_static_library("browser") {
     "password_manager/password_store_mac.h",
     "password_manager/password_store_win.cc",
     "password_manager/password_store_win.h",
+    "payments/payment_handler_permission_context.cc",
+    "payments/payment_handler_permission_context.h",
     "payments/ssl_validity_checker.cc",
     "payments/ssl_validity_checker.h",
     "performance_monitor/performance_monitor.cc",
@@ -3222,6 +3224,8 @@ split_static_library("browser") {
       "payments/android/payment_manifest_web_data_service_android.h",
       "payments/android/ssl_validity_checker_android.cc",
       "payments/android/ssl_validity_checker_android.h",
+      "payments/payment_handler_permission_infobar_delegate.cc",
+      "payments/payment_handler_permission_infobar_delegate.h",
       "permissions/grouped_permission_infobar_delegate_android.cc",
       "permissions/grouped_permission_infobar_delegate_android.h",
       "permissions/permission_dialog_delegate.cc",