Add Sync data type for managed users.

sync/internal_api/write_node.cc

Index: sync/internal_api/write_node.cc
diff --git a/sync/internal_api/write_node.cc b/sync/internal_api/write_node.cc
index db461d6cdb6c2261da1884917431622bcd1e5592..22496c1fddd578a2d12b1428388951dbe7efa443 100644
--- a/sync/internal_api/write_node.cc
+++ b/sync/internal_api/write_node.cc
@@ -193,6 +193,13 @@ void WriteNode::SetManagedUserSettingSpecifics(
   SetEntitySpecifics(entity_specifics);
 }
 
+void WriteNode::SetManagedUserSpecifics(
+    const sync_pb::ManagedUserSpecifics& new_value) {
+  sync_pb::EntitySpecifics entity_specifics;
+  entity_specifics.mutable_managed_user()->CopyFrom(new_value);
+  SetEntitySpecifics(entity_specifics);
+}
+
 void WriteNode::SetDeviceInfoSpecifics(
     const sync_pb::DeviceInfoSpecifics& new_value) {
   sync_pb::EntitySpecifics entity_specifics;