[Payments] Add an entry for Payment Request to chrome://flags on iOS

components/payments/core/features.cc

Index: components/payments/core/features.cc
diff --git a/components/payments/core/features.cc b/components/payments/core/features.cc
new file mode 100644
index 0000000000000000000000000000000000000000..183396de7bb3bf322f590c122c7fec121a0238ba
--- /dev/null
+++ b/components/payments/core/features.cc
@@ -0,0 +1,16 @@
+// Copyright 2017 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.
+
+#include "components/payments/core/features.h"
+
+namespace payments {
+namespace features {
+
+#if defined(OS_IOS)
+const base::Feature kWebPayments{"WebPayments",
+                                 base::FEATURE_DISABLED_BY_DEFAULT};
+#endif
+
+}  // namespace features
+}  // namespace payments