Use {To/From}JavaTime for policy timestamps

components/policy/proto/device_management_backend.proto

 // 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.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
 package enterprise_management;
 
@@ skipping 183 matching lines @@
   // Possible values for Chrome OS are:
   //   google/chromeos/device => ChromeDeviceSettingsProto
   //   google/chromeos/user => ChromeSettingsProto
   //   google/chromeos/publicaccount => ChromeSettingsProto
   //   google/chrome/extension => ExternalPolicyData
   //   google/chromeos/signinextension => ExternalPolicyData
   //   google/android/user => ChromeSettingsProto
   //   google/ios/user => ChromeSettingsProto
   optional string policy_type = 1;
 
-  // This is the last policy timestamp that client received from server.
+  // This is the last policy timestamp that client received from server. The
+  // expectation is that this field is filled by the value of
+  // PolicyData.timestamp from the last policy received by the client.
   optional int64 timestamp = 2;
 
   // Tell server what kind of security signature is required.
   enum SignatureType {
     NONE = 0;
     SHA1_RSA = 1;
   }
   optional SignatureType signature_type = 3 [default = NONE];
 
   // The version number of the public key that is currently stored
@@ skipping 63 matching lines @@
   // |DEVICE_MODE_DISABLED|.
   optional DisabledState disabled_state = 2;
 }
 
 // This message is included in serialized form in PolicyFetchResponse below. It
 // may also be signed, with the signature being created for the serialized form.
 message PolicyData {
   // See PolicyFetchRequest.policy_type.
   optional string policy_type = 1;
 
-  // [timestamp] is milliseconds since Epoch in UTC timezone. It is
-  // included here so that the time at which the server issued this
-  // response cannot be faked (as protection against replay attacks).
-  // It is the timestamp generated by DMServer, NOT the time admin
-  // last updated the policy or anything like that.
+  // [timestamp] is milliseconds since Epoch in UTC timezone (Java time). It is
+  // included here so that the time at which the server issued this response
+  // cannot be faked (as protection against replay attacks). It is the timestamp
+  // generated by DMServer, NOT the time admin last updated the policy or
+  // anything like that.
   optional int64 timestamp = 2;
 
   // The DM token that was used by the client in the HTTP POST header
   // for authenticating the request. It is included here again so that
   // the client can verify that the response is meant for them (and not
   // issued by a replay or man-in-the-middle attack).
   optional string request_token = 3;
 
   // The serialized value of the actual policy protobuf.  This can be
   // deserialized to an instance of, for example, ChromeSettingsProto,
@@ skipping 226 matching lines @@
   repeated PolicyFetchRequest request = 3;
 }
 
 // Response from server to device for reading policies.
 message DevicePolicyResponse {
   // The policy fetch response.
   repeated PolicyFetchResponse response = 3;
 }
 
 message TimePeriod {
-  // [timestamp] is milli seconds since Epoch in UTC timezone.
+  // [timestamp] is milliseconds since Epoch in UTC timezone (Java time).
   optional int64 start_timestamp = 1;
   optional int64 end_timestamp = 2;
 }
 
 message ActiveTimePeriod {
   optional TimePeriod time_period = 1;
 
   // The active duration during the above time period.
   // The unit is milli-second.
   optional int32 active_duration = 2;
@@ skipping 466 matching lines @@
     RESULT_SUCCESS = 2;  // The command was successfully executed.
   }
 
   // The result of the command.
   optional ResultType result = 1;
 
   // The opaque unique identifier of the command. This value is copied from the
   // RemoteCommand protobuf that contained the command.
   optional int64 command_id = 2;
 
-  // The time at which the command was executed, if the the result is
-  // RESULT_SUCCESS.
+  // The timestamp representing time at which the command was executed, if the
+  // result is RESULT_SUCCESS. The timestamp is milliseconds since Epoch in UTC
+  // timezone (Java time).
   optional int64 timestamp = 3;
 
   // Extra information sent to server as result of execution, expected to be a
   // JSON string.
   optional string payload = 4;
 }
 
 message DeviceRemoteCommandRequest {
   // The command ID of the last command received from the server until
   // now.  Omitted if no commands have been received yet.
@@ skipping 369 matching lines @@
       check_android_management_response = 18;
 
   // Response to an Active Directory Play user enrollment request.
   optional ActiveDirectoryEnrollPlayUserResponse
       active_directory_enroll_play_user_response = 19;
 
   // Response to a Play activity request.
   optional ActiveDirectoryPlayActivityResponse
       active_directory_play_activity_response = 20;
 }