[rac] Use stale libaddressinput data if download fails

third_party/libaddressinput/chromium/cpp/src/validating_util.h

-// Copyright (C) 2013 Google Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-// An object to wrap data with a checksum and a timestamp. These fields are used
-// to verify that the data is not stale or corrupted. Staleness threshold is 1
-// month.
-
-#ifndef I18N_ADDRESSINPUT_VALIDATING_UTIL_H_
-#define I18N_ADDRESSINPUT_VALIDATING_UTIL_H_
-
-#include <ctime>
-#include <string>
-
-namespace i18n {
-namespace addressinput {
-
-// Wraps data with a checksum and a timestamp. Sample usage:
-//    std::string data  = ...
-//    std::string wrapped = ValidatingUtil::Wrap(data, time(NULL));
-//    Process(wrapped);
-//
-//    std::string unwrapped = wrapped;
-//    if (ValidatingUtil::UnwrapTimestamp(&unwrapped, time(NULL)) &&
-//        ValidatingUtil::UnwrapChecksum(&unwrapped)) {
-//      Process(unwrapped);
-//    }
-class ValidatingUtil {
- public:
-  // Returns |data| with attached checksum and given |timestamp|.
-  static std::string Wrap(const std::string& data, time_t timestamp);
-
-  // Strips out the timestamp from |data|. Returns |true| if the timestamp is
-  // present, formatted correctly, valid, and recent with respect to |now|.
-  static bool UnwrapTimestamp(std::string* data, time_t now);
-
-  // Strips out the checksum from |data|. Returns |true| if the checksum is
-  // present, formatted correctly, and valid for this data.
-  static bool UnwrapChecksum(std::string* data);
-};
-
-}  // namespace addressinput
-}  // namespace i18n
-
-#endif  // I18N_ADDRESSINPUT_VALIDATING_UTIL_H_