Add device policy to enable ephemeral users

chrome/browser/policy/proto/chrome_device_policy.proto

 // 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.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
 package enterprise_management;
 
@@ skipping 74 matching lines @@
   optional string open_network_configuration = 1;
 }
 
 // Policies to turn on portions of the device status reports.
 message DeviceReportingProto {
   optional bool report_version_info = 1;
   optional bool report_activity_times = 2;
   optional bool report_boot_mode = 3;
 }
 
+message EphemeralUsersProto {
+  // Determines whether users should be treated as ephemeral.
+  optional bool ephemeral_users = 1;
+}
+
 message ChromeDeviceSettingsProto {
   optional DevicePolicyRefreshRateProto device_policy_refresh_rate = 1;
   optional UserWhitelistProto user_whitelist = 2;
   optional GuestModeEnabledProto guest_mode_enabled = 3;
   optional DeviceProxySettingsProto device_proxy_settings = 4;
   optional CameraEnabledProto camera_enabled = 5;
   optional ShowUserNamesOnSigninProto show_user_names = 6;
   optional DataRoamingEnabledProto data_roaming_enabled = 7;
   optional AllowNewUsersProto allow_new_users = 8;
   optional MetricsEnabledProto metrics_enabled = 9;
   optional ReleaseChannelProto release_channel = 10;
   optional DeviceOpenNetworkConfigurationProto open_network_configuration = 11;
   optional DeviceReportingProto device_reporting = 12;
+  optional EphemeralUsersProto ephemeral_users = 13;
 }