Remove the "not_after" validation of policy timestamps

chrome/browser/chromeos/settings/session_manager_operation.cc

 // Copyright (c) 2012 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 "chrome/browser/chromeos/settings/session_manager_operation.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 153 matching lines @@
           pool->GetSequenceToken(),
           base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
 
   std::unique_ptr<policy::DeviceCloudPolicyValidator> validator =
       base::WrapUnique<policy::DeviceCloudPolicyValidator>(
           policy::DeviceCloudPolicyValidator::Create(std::move(policy),
                                                      background_task_runner));
 
   if (cloud_validations_) {
     // Policy auto-generated by session manager doesn't include a timestamp, so
-    // the timestamp shouldn't be verified in that case.
-    //
-    // Additionally, offline devices can get their clock set backwards in time
-    // under some hardware conditions; checking the timestamp now could likely
-    // find a value in the future, and prevent the user from signing-in or
-    // starting guest mode. Tlsdate will eventually fix the clock when the
-    // device is back online, but the network configuration may come from device
-    // ONC.
-    //
-    // To prevent all of these issues the timestamp is just not verified when
-    // loading the device policy from session manager. Note that the timestamp
+    // the timestamp shouldn't be verified in that case. Note that the timestamp
     // is still verified during enrollment and when a new policy is fetched from
     // the server.
     //
     // The two *_NOT_REQUIRED options are necessary because both the DM token
     // and the device id are empty for a user logging in on an actual Chrome OS
     // device that is not enterprise-managed. Note for devs: The strings are not
     // empty when you test Chrome with target_os = "chromeos" on Linux!
     validator->ValidateAgainstCurrentPolicy(
         policy_data_.get(),
         policy::CloudPolicyValidatorBase::TIMESTAMP_NOT_VALIDATED,
@@ skipping 78 matching lines @@
 }
 
 void StoreSettingsOperation::HandleStoreResult(bool success) {
   if (!success)
     ReportResult(DeviceSettingsService::STORE_OPERATION_FAILED);
   else
     StartLoading();
 }
 
 }  // namespace chromeos