Add a datatype for supervised user whitelists.

sync/protocol/managed_user_whitelist_specifics.proto

Index: sync/protocol/managed_user_whitelist_specifics.proto
diff --git a/sync/protocol/managed_user_whitelist_specifics.proto b/sync/protocol/managed_user_whitelist_specifics.proto
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index 0000000000000000000000000000000000000000..e92dbfdbea2921b2cabfc67a4b11734e2387820d
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+++ b/sync/protocol/managed_user_whitelist_specifics.proto
@@ -0,0 +1,25 @@
+// Copyright (c) 2014 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 supervised user whitelists.
+
+// Update proto_value_conversions{.h,.cc,_unittest.cc} if you change
+// any fields in this file.
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+option retain_unknown_fields = true;
+
+package sync_pb;
+
+// Properties of supervised user whitelist sync objects.
+// The fields here are a subset of the fields in an ExtensionSpecifics.
+message ManagedUserWhitelistSpecifics {
+  // Globally unique id for this whitelist that identifies it in the Web Store.
+  optional string id = 1;
+
+  // The name of the whitelist.
+  optional string name = 2;
+}