[Web Payment] Secure payment confirmation debug flag.

Before this patch, PaymentCredential in WebAuthn and secure payment
confirmation method in PaymentRequest API always required a user
verifying platform authenticator device, which made testing difficult on
Linux with UbiKey, for example.

This patch adds a
chrome://flags/#enable-debug-for-secure-payment-confirmation flag to
remove the user verifying platform authenticator restriction.

After this patch, web developers can test secure payment confirmation in
such use cases as on Linux with UbiKey.

Bug: 1122715
Change-Id: I270dcd07ba7cbf2b8f6cedb8f4fad2bf0e5968e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2379955
Reviewed-by: Kinuko Yasuda <[email protected]>
Reviewed-by: Ken Buchanan <[email protected]>
Commit-Queue: Rouslan Solomakhin <[email protected]>
Cr-Commit-Position: refs/heads/master@{#802606}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 360b7ab..bc07417 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -3520,6 +3520,10 @@
      flag_descriptions::kAppStoreBillingDebugName,
      flag_descriptions::kAppStoreBillingDebugDescription, kOsAll,
      FEATURE_VALUE_TYPE(payments::features::kAppStoreBillingDebug)},
+    {"enable-debug-for-secure-payment-confirmation",
+     flag_descriptions::kSecurePaymentConfirmationDebugName,
+     flag_descriptions::kSecurePaymentConfirmationDebugDescription, kOsAll,
+     FEATURE_VALUE_TYPE(features::kSecurePaymentConfirmationDebug)},
     {"fill-on-account-select", flag_descriptions::kFillOnAccountSelectName,
      flag_descriptions::kFillOnAccountSelectDescription, kOsAll,
      FEATURE_VALUE_TYPE(password_manager::features::kFillOnAccountSelect)},