Remove the "not_after" validation of policy timestamps

chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc

Index: chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
diff --git a/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc b/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
index 23e9cf982ca6e83c6f415eeca70d9b51726f0105..89f67ba22058161f8ce6730d664efda05ce7b6d6 100644
--- a/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
+++ b/chrome/browser/chromeos/policy/enrollment_handler_chromeos.cc
@@ -199,9 +199,8 @@ void EnrollmentHandlerChromeOS::OnPolicyFetched(CloudPolicyClient* client) {
           base::MakeUnique<em::PolicyFetchResponse>(*policy),
           background_task_runner_));
 
-  validator->ValidateTimestamp(
-      base::Time(), base::Time::NowFromSystemTime(),
-      CloudPolicyValidatorBase::TIMESTAMP_FULLY_VALIDATED);
+  validator->ValidateTimestamp(base::Time(),
+                               CloudPolicyValidatorBase::TIMESTAMP_VALIDATED);
 
   // If this is re-enrollment, make sure that the new policy matches the
   // previously-enrolled domain.  (Currently only implemented for cloud