Use {To/From}JavaTime for policy timestamps

chrome/browser/policy/cloud/cloud_policy_invalidator.cc

 // Copyright 2013 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/policy/cloud/cloud_policy_invalidator.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/hash.h"
@@ skipping 373 matching lines @@
   // previous policy's hash value.
   uint32_t new_hash_value = 0;
   if (policy && policy->has_policy_value())
     new_hash_value = base::Hash(policy->policy_value());
   bool changed = new_hash_value != policy_hash_value_;
   policy_hash_value_ = new_hash_value;
   return changed;
 }
 
 bool CloudPolicyInvalidator::IsInvalidationExpired(int64_t version) {
-  base::Time last_fetch_time = base::Time::UnixEpoch() +
-      base::TimeDelta::FromMilliseconds(core_->store()->policy()->timestamp());
+  base::Time last_fetch_time =
+      base::Time::FromJavaTime(core_->store()->policy()->timestamp());
 
   // If the version is unknown, consider the invalidation invalid if the
   // policy was fetched very recently.
   if (version < 0) {
     base::TimeDelta elapsed = clock_->Now() - last_fetch_time;
     return elapsed.InSeconds() < kUnknownVersionIgnorePeriod;
   }
 
   // The invalidation version is the timestamp in microseconds. If the
   // invalidation occurred before the last policy fetch, then the invalidation
@@ skipping 33 matching lines @@
 bool CloudPolicyInvalidator::GetInvalidationsEnabled() {
   if (!invalidations_enabled_)
     return false;
   // If invalidations have been enabled for less than the grace period, then
   // consider invalidations to be disabled for metrics reporting.
   base::TimeDelta elapsed = clock_->Now() - invalidations_enabled_time_;
   return elapsed.InSeconds() >= kInvalidationGracePeriod;
 }
 
 }  // namespace policy