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

chrome/browser/chromeos/policy/consumer_management_service.cc

 // Copyright 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.
 
 #include "chrome/browser/chromeos/policy/consumer_management_service.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/prefs/pref_registry_simple.h"
@@ skipping 103 matching lines @@
 void ConsumerManagementService::GetOwner(const GetOwnerCallback& callback) {
   cryptohome::GetBootAttributeRequest request;
   request.set_name(kAttributeOwnerId);
   client_->GetBootAttribute(
       request,
       base::Bind(&ConsumerManagementService::OnGetBootAttributeDone,
                  weak_ptr_factory_.GetWeakPtr(),
                  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,
                  weak_ptr_factory_.GetWeakPtr(),
                  callback));
 }
 
 void ConsumerManagementService::OwnershipStatusChanged() {
 }
 
@@ skipping 51 matching lines @@
   if (!dbus_success || reply.error() != 0) {
     LOG(ERROR) << "Failed to flush and sign boot lockbox.";
     callback.Run(false);
     return;
   }
 
   callback.Run(true);
 }
 
 }  // namespace policy