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

chrome/browser/chromeos/profiles/profile_helper.cc

 // Copyright (c) 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.
 
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 
 #include "base/barrier_closure.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 148 matching lines @@
 
 // static
 bool ProfileHelper::IsOwnerProfile(Profile* profile) {
   if (!profile)
     return false;
   const user_manager::User* user =
       ProfileHelper::Get()->GetUserByProfile(profile);
   if (!user)
     return false;
 
-  return user->email() == user_manager::UserManager::Get()->GetOwnerEmail();
+  return user->GetUserID() == user_manager::UserManager::Get()->GetOwnerID();
 }
 
 // static
 bool ProfileHelper::IsPrimaryProfile(const Profile* profile) {
   if (!profile)
     return false;
   const user_manager::User* user =
       ProfileHelper::Get()->GetUserByProfile(profile);
   if (!user)
     return false;
@@ skipping 94 matching lines @@
   }
 
   Profile* profile = NULL;
   if (user->is_profile_created()) {
     profile = ProfileHelper::GetProfileByUserIdHash(user->username_hash());
   } else {
     LOG(WARNING) << "ProfileHelper::GetProfileByUserUnsafe is called when "
                     "|user|'s profile is not created. It probably means that "
                     "something is wrong with a calling code. Please report in "
                     "http://crbug.com/361528 if you see this message. user_id: "
-                 << user->email();
+                 << user->GetUserID().GetUserEmail();
     profile = ProfileManager::GetActiveUserProfile();
   }
 
   // GetActiveUserProfile() or GetProfileByUserIdHash() returns a new instance
   // of ProfileImpl(), but actually its OffTheRecordProfile() should be used.
   if (profile && user_manager::UserManager::Get()->IsLoggedInAsGuest())
     profile = profile->GetOffTheRecordProfile();
   return profile;
 }
 
 const user_manager::User* ProfileHelper::GetUserByProfile(
     const Profile* profile) const {
   // This map is non-empty only in tests.
   if (enable_profile_to_user_testing || !user_list_for_testing_.empty()) {
     if (always_return_primary_user_for_testing)
       return user_manager::UserManager::Get()->GetPrimaryUser();
 
-    const std::string& user_name = profile->GetProfileUserName();
+    const user_manager::UserID user_id = user_manager::UserID::FromUserEmail(profile->GetProfileUserName());
     for (user_manager::UserList::const_iterator it =
              user_list_for_testing_.begin();
          it != user_list_for_testing_.end();
          ++it) {
-      if ((*it)->email() == user_name)
+      if ((*it)->GetUserID() == user_id)
         return *it;
     }
 
     // In case of test setup we should always default to primary user.
     return user_manager::UserManager::Get()->GetPrimaryUser();
   }
 
   DCHECK(!content::BrowserThread::IsThreadInitialized(
              content::BrowserThread::UI) ||
          content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
@@ skipping 103 matching lines @@
   user_to_profile_for_testing_[user] = profile;
 }
 
 // static
 std::string ProfileHelper::GetUserIdHashByUserIdForTesting(
     const std::string& user_id) {
   return user_id + kUserIdHashSuffix;
 }
 
 }  // namespace chromeos