PaymentHandler: Implement PaymentInstruments.keys().

content/browser/service_worker/service_worker_database.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 CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 180 matching lines @@
                             RegistrationData* deleted_version,
                             std::vector<int64_t>* newly_purgeable_resources);
 
   // Reads user data for |registration_id| and |user_data_names| from the
   // database. Returns OK only if all keys are found; otherwise NOT_FOUND, and
   // |user_data_values| will be empty.
   Status ReadUserData(int64_t registration_id,
                       const std::vector<std::string>& user_data_names,
                       std::vector<std::string>* user_data_values);
 
+  // Reads user data for |registration_id| and |key_prefix| from the database.
+  // Returns OK only if all keys are found; otherwise NOT_FOUND, and

[nhiroki, 2017/05/02 01:21:12]

"all keys are found" sounds strange. Maybe "if keys matched to |key_prefix| are
found"?

[zino, 2017/05/02 15:03:58]

Done.

+  // |user_data_values| will be empty.
+  Status ReadUserDataByKeyPrefix(int64_t registration_id,
+                                 const std::string key_prefix,
+                                 std::vector<std::string>* user_data_values);
+
   // Writes |name_value_pairs| into the database. Returns NOT_FOUND if the
   // registration specified by |registration_id| does not exist in the database.
   Status WriteUserData(
       int64_t registration_id,
       const GURL& origin,
       const std::vector<std::pair<std::string, std::string>>& name_value_pairs);
 
   // Deletes user data for |registration_id| and |user_data_names| from the
   // database. Returns OK if all are successfully deleted or not found in the
   // database.
@@ skipping 190 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest,
                            UserData_UninitializedDatabase);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, DestroyDatabase);
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerDatabase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_