PaymentHandler: Implement requestPermission().

components/content_settings/core/common/content_settings_types.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_TYPES_H_
 #define COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_TYPES_H_
 
 #include <cstddef>
 
 #include "build/build_config.h"
@@ skipping 49 matching lines @@
 
   // This is only here temporarily and will be removed when we further unify
   // it with notifications, see crbug.com/563297. No prefs data is stored for
   // this content type, we instead share values with NOTIFICATIONS.
   CONTENT_SETTINGS_TYPE_PUSH_MESSAGING,
 
   // This content setting type is for caching password protection service's
   // verdicts of each origin.
   CONTENT_SETTINGS_TYPE_PASSWORD_PROTECTION,
 
+  // This content setting type is whether to allow installing a payment handler.
+  CONTENT_SETTINGS_TYPE_PAYMENT_HANDLER,
+
   // WARNING: This enum is going to be removed soon. Do not depend on NUM_TYPES.
   CONTENT_SETTINGS_NUM_TYPES_DO_NOT_USE,
 };
 
 struct ContentSettingsTypeHash {
   std::size_t operator()(ContentSettingsType type) const {
     return static_cast<std::size_t>(type);
   }
 };
 
 #endif  // COMPONENTS_CONTENT_SETTINGS_CORE_COMMON_CONTENT_SETTINGS_TYPES_H_