kiosk: Support update url for enterprise.

chrome/browser/chromeos/policy/proto/chrome_device_policy.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 245 matching lines @@
   optional bool use_24hour_clock = 1;
 }
 
 // Parameters for Kiosk App device-local accounts.
 message KioskAppInfoProto {
   // Indicates the Kiosk App for the corresponding device-local account. The
   // string value should be a valid 32-character Chrome App identifier and
   // specifies the Kiosk App to download and run.
   optional string app_id = 1;
 
-  // Obsolete: Kiosk Apps can only be installed from the Chrome Web Store.
-  optional string OBSOLETE_update_url = 2 [deprecated = true];
+  // Optional extension update URL to download the Kiosk App package from. If
+  // not specified, the app will be downloaded from the standard Chrome Web
+  // Store update URL.
+  optional string update_url = 2;
 }
 
 // Describes a single device-local account.
 message DeviceLocalAccountInfoProto {
   // Deprecated: Account identifier for a public session device-local account.
   // Old code didn't have the |type| field, so it can't handle new types of
   // device-local accounts gracefully (i.e. ignoring unsupported types). New
   // code should instead set type to ACCOUNT_TYPE_PUBLIC_SESSION and write the
   // identifier to the |account_id| field below. If the |type| field is present,
   // |deprecated_public_session_id| will be ignored.
@@ skipping 331 matching lines @@
   optional VariationsParameterProto variations_parameter = 25;
   optional AttestationSettingsProto attestation_settings = 26;
   optional AccessibilitySettingsProto accessibility_settings = 27;
   optional SupervisedUsersSettingsProto supervised_users_settings = 28;
   optional LoginScreenPowerManagementProto login_screen_power_management = 29;
   optional SystemUse24HourClockProto use_24hour_clock = 30;
   optional AutoCleanupSettigsProto auto_clean_up_settings = 31;
   optional SystemSettingsProto system_settings = 32;
   optional SAMLSettingsProto saml_settings = 33;
 }