Retire PaymentRequestBasicCard flag

Support for basic card payment method specification shipped in M57.
https://codereview.chromium.org/2501593003
https://www.chromestatus.com/feature/5408502604365824

BUG=665190

Change-Id: I29780c35a6ccf5c9d5a94b21e38d8605ba8b77f9
Reviewed-on: https://chromium-review.googlesource.com/1166744Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581754}

third_party/blink/renderer/modules/payments/payment_request.cc

@@ -52,7 +52,6 @@
 #include "third_party/blink/renderer/platform/bindings/script_state.h"
 #include "third_party/blink/renderer/platform/feature_policy/feature_policy.h"
 #include "third_party/blink/renderer/platform/mojo/mojo_helper.h"
-#include "third_party/blink/renderer/platform/runtime_enabled_features.h"
 #include "third_party/blink/renderer/platform/uuid.h"
 #include "third_party/blink/renderer/platform/weborigin/kurl.h"
 #include "third_party/blink/renderer/platform/wtf/hash_set.h"
@@ -518,8 +517,7 @@ void StringifyAndParseMethodSpecificData(const String& supported_method,
     if (exception_state.HadException())
       exception_state.ClearException();
   }
-  if (RuntimeEnabledFeatures::PaymentRequestBasicCardEnabled() &&
-      supported_method == "basic-card") {
+  if (supported_method == "basic-card") {
     SetBasicCardMethodData(input, output, exception_state);
     if (exception_state.HadException())
       exception_state.ClearException();

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -934,10 +934,6 @@
       name: "PaymentRequest",
       status: "experimental",
     },
-    {
-      name: "PaymentRequestBasicCard",
-      status: "stable",
-    },
     {
       name: "PaymentRetry",
       status: "experimental",