Use {To/From}JavaTime for policy timestamps

components/policy/core/common/cloud/cloud_policy_client_unittest.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 "components/policy/core/common/cloud/cloud_policy_client.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <map>
@@ skipping 519 matching lines @@
   Register();
 
   const base::Time timestamp(
       base::Time::UnixEpoch() + base::TimeDelta::FromDays(20));
   client_->set_submit_machine_id(true);
   client_->set_last_policy_timestamp(timestamp);
   client_->set_public_key_version(42);
   em::PolicyFetchRequest* policy_fetch_request =
       policy_request_.mutable_policy_request()->mutable_request(0);
   policy_fetch_request->set_machine_id(kMachineID);
-  policy_fetch_request->set_timestamp(
-      (timestamp - base::Time::UnixEpoch()).InMilliseconds());
+  policy_fetch_request->set_timestamp(timestamp.ToJavaTime());
   policy_fetch_request->set_public_key_version(42);
 
   ExpectPolicyFetch(kDMToken);
   EXPECT_CALL(observer_, OnPolicyFetched(_));
   client_->FetchPolicy();
   CheckPolicyResponse();
 }
 
 TEST_F(CloudPolicyClientTest, PolicyFetchWithInvalidation) {
   Register();
@@ skipping 397 matching lines @@
   EXPECT_CALL(callback_observer_, OnCallbackComplete(true)).Times(1);
 
   CloudPolicyClient::StatusCallback callback =
       base::Bind(&MockStatusCallbackObserver::OnCallbackComplete,
                  base::Unretained(&callback_observer_));
   client_->UpdateGcmId(kGcmID, callback);
   EXPECT_EQ(DM_STATUS_SUCCESS, client_->status());
 }
 
 }  // namespace policy