No rate limit for canMakePayment() on localhost and file://.

components/payments/mojom/payment_request.mojom

 // 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.
 
 [JavaPackage="org.chromium.payments.mojom"]
 module payments.mojom;
 
 // The shipping address that the browser process provides to the renderer
 // process. Built either by the browser or a payment app.
 struct PaymentAddress {
@@ skipping 62 matching lines @@
 
 enum PaymentErrorReason {
   UNKNOWN,
   USER_CANCEL,
   NOT_SUPPORTED
 };
 
 enum CanMakePaymentQueryResult {
   CAN_MAKE_PAYMENT,
   CANNOT_MAKE_PAYMENT,
-  QUERY_QUOTA_EXCEEDED
+  QUERY_QUOTA_EXCEEDED,
+
+  // Used only on localhost and file:// schemes to warn web developer that the
+  // query quota has exceeded, but Chrome is returning an answer anyway.
+  WARNING_CAN_MAKE_PAYMENT,
+  WARNING_CANNOT_MAKE_PAYMENT,
 };
 
 interface PaymentRequestClient {
   OnShippingAddressChange(PaymentAddress address);
   OnShippingOptionChange(string shipping_option_id);
   OnPaymentResponse(PaymentResponse response);
   OnError(PaymentErrorReason error);
   OnComplete();
   OnAbort(bool aborted_successfully);
   OnCanMakePayment(CanMakePaymentQueryResult result);
@@ skipping 120 matching lines @@
   Init(PaymentRequestClient client,
        array<PaymentMethodData> method_data,
        PaymentDetails details,
        PaymentOptions options);
   Show();
   UpdateWith(PaymentDetails details);
   Abort();
   Complete(PaymentComplete result);
   CanMakePayment();
 };