Revert "Sync: Delete deprecated SUPERVISED_USERS and SHARED_SETTINGS data types"

This reverts the proto changes from commit d70c086c.

Reason for revert: Server side code has a lot of dependencies that need to be cleaned up first.

Original change's description:
> Sync: Delete deprecated SUPERVISED_USERS and _SHARED_SETTINGS data types
>
> These two types are deprecated and can be removed. Note that
> SUPERVISER_USER_SETTINGS and SUPERVISED_USER_WHITELISTS are *not*
> deprecated.
>
> This includes removing the ModelType enum entries, removing the fields
> in the EntitySpecifics proto, and deleting the specifics proto files.
>
> Bug: 965503
> Change-Id: I53038fdc28ed8518cd99d4a4769b5f1f52d3e94b
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1824882
> Commit-Queue: Marc Treib <treib@chromium.org>
> Reviewed-by: Mikel Astiz <mastiz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#700687}

TBR=treib@chromium.org,mastiz@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 965503
Change-Id: If5d1ee616f2ca4daefe69fd1e0ad3a516d726675
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1863789Reviewed-by: Tim Schumann <tschumann@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Tim Schumann <tschumann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706347}

components/sync/protocol/managed_user_shared_setting_specifics.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.
+//
+// Sync protocol datatype extension for managed user shared settings.
+
+// If you change or add any fields in this file, update proto_visitors.h and
+// potentially proto_enum_conversions.{h, cc}.
+
+syntax = "proto2";
+
+option java_multiple_files = true;
+option java_package = "org.chromium.components.sync.protocol";
+
+option optimize_for = LITE_RUNTIME;
+
+package sync_pb;
+
+// Properties of managed user shared setting sync objects.
+message ManagedUserSharedSettingSpecifics {
+  // The MU ID for the managed user to whom the setting applies.
+  optional string mu_id = 1;
+  // The key of the setting.
+  optional string key = 2;
+  // The setting value. The setting is a JSON encoding of an arbitrary
+  // Javascript value.
+  optional string value = 3;
+  // This flag is set by the server to acknowledge that it has committed a
+  // change to a setting.
+  optional bool acknowledged = 4 [default = false];
+}

components/sync/protocol/managed_user_specifics.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.
+//
+// Sync protocol datatype extension for managed user settings.
+
+// If you change or add any fields in this file, update proto_visitors.h and
+// potentially proto_enum_conversions.{h, cc}.
+
+syntax = "proto2";
+
+option java_multiple_files = true;
+option java_package = "org.chromium.components.sync.protocol";
+
+option optimize_for = LITE_RUNTIME;
+
+package sync_pb;
+
+// Properties of managed user sync objects.
+message ManagedUserSpecifics {
+  // A randomly-generated identifier for the managed user.
+  optional string id = 1;
+  // The human-visible name of the managed user
+  optional string name = 2;
+  // This flag is set by the server to acknowledge that it has committed a
+  // newly created managed user.
+  optional bool acknowledged = 3 [default = false];
+  // Master key for managed user cryptohome.
+  optional string master_key = 4;
+  // A string representing the index of the supervised user avatar on Chrome.
+  // It has the following format:
+  // "chrome-avatar-index:INDEX" where INDEX is an integer.
+  optional string chrome_avatar = 5;
+  // A string representing the index of the supervised user avatar on Chrome OS.
+  // It has the following format:
+  // "chromeos-avatar-index:INDEX" where INDEX is an integer.
+  optional string chromeos_avatar = 6;
+  // Key for signing supervised user's password.
+  optional string password_signature_key = 7;
+  // Key for encrypting supervised user's password.
+  optional string password_encryption_key = 8;
+}

components/sync/protocol/protocol_sources.gni

@@ -30,6 +30,8 @@ sync_protocol_bases = [
   "history_status",
   "loopback_server",
   "managed_user_setting_specifics",
+  "managed_user_shared_setting_specifics",
+  "managed_user_specifics",
   "managed_user_whitelist_specifics",
   "model_type_state",
   "model_type_store_schema_descriptor",

components/sync/protocol/sync.proto

@@ -37,6 +37,8 @@ import "favicon_tracking_specifics.proto";
 import "get_updates_caller_info.proto";
 import "history_delete_directive_specifics.proto";
 import "managed_user_setting_specifics.proto";
+import "managed_user_shared_setting_specifics.proto";
+import "managed_user_specifics.proto";
 import "managed_user_whitelist_specifics.proto";
 import "mountain_share_specifics.proto";
 import "nigori_specifics.proto";
@@ -143,6 +145,11 @@ message EntitySpecifics {
     FaviconTrackingSpecifics favicon_tracking = 181534;
     FaviconImageSpecifics favicon_image = 182019;
     ManagedUserSettingSpecifics managed_user_setting = 186662;
+    // TODO(tschumann): Remove once server-side dependencies are resolved.
+    ManagedUserSpecifics managed_user = 194582 [deprecated = true];
+    // TODO(tschumann): Remove once server-side dependencies are resolved.
+    ManagedUserSharedSettingSpecifics managed_user_shared_setting = 202026
+        [deprecated = true];
     ManagedUserWhitelistSpecifics managed_user_whitelist = 306060;
     AppListSpecifics app_list = 229170;
     AutofillWalletSpecifics autofill_wallet = 306270;
@@ -160,10 +167,6 @@ message EntitySpecifics {
     OsPreferenceSpecifics os_preference = 702141;
     OsPriorityPreferenceSpecifics os_priority_preference = 703915;
   }
-  reserved 194582;
-  reserved "managed_user";
-  reserved 202026;
-  reserved "managed_user_shared_setting";
   reserved 218175;
   reserved "wifi_credential";
   reserved 223759;