We should use UserID object to identify users instead of username.

chrome/browser/chromeos/policy/consumer_management_service.cc

Index: chrome/browser/chromeos/policy/consumer_management_service.cc
diff --git a/chrome/browser/chromeos/policy/consumer_management_service.cc b/chrome/browser/chromeos/policy/consumer_management_service.cc
index 2e64d9b582991b9d04272930b81c24cec968c4a1..6ab1cf63008d5e57baaf1c53586bcd1eb165ca43 100644
--- a/chrome/browser/chromeos/policy/consumer_management_service.cc
+++ b/chrome/browser/chromeos/policy/consumer_management_service.cc
@@ -121,11 +121,12 @@ void ConsumerManagementService::GetOwner(const GetOwnerCallback& callback) {
                  callback));
 }
 
-void ConsumerManagementService::SetOwner(const std::string& user_id,
+void ConsumerManagementService::SetOwner(const user_manager::UserID& user_id,
                                          const SetOwnerCallback& callback) {
+  const std::string& user_email = user_id.GetUserEmail();
   cryptohome::SetBootAttributeRequest request;
   request.set_name(kAttributeOwnerId);
-  request.set_value(user_id.data(), user_id.size());
+  request.set_value(user_email.data(), user_email.size());
   client_->SetBootAttribute(
       request,
       base::Bind(&ConsumerManagementService::OnSetBootAttributeDone,