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

components/user_manager/user_manager_base.cc

Index: components/user_manager/user_manager_base.cc
diff --git a/components/user_manager/user_manager_base.cc b/components/user_manager/user_manager_base.cc
index 3e11ff871068bace74871ce0cb3bbe828229cce5..430d94c048e99b4ec6c0e8201a260a6ad03a1fa5 100644
--- a/components/user_manager/user_manager_base.cc
+++ b/components/user_manager/user_manager_base.cc
@@ -96,12 +96,12 @@ const char kReauthReasonKey[] = "reauth_reason";
 const int kLogoutToLoginDelayMaxSec = 1800;
 
 // Callback that is called after user removal is complete.
-void OnRemoveUserComplete(const std::string& user_email,
+void OnRemoveUserComplete(const UserID& user_id,
                           bool success,
                           cryptohome::MountError return_code) {
   // Log the error, but there's not much we can do.
   if (!success) {
-    LOG(ERROR) << "Removal of cryptohome for " << user_email
+    LOG(ERROR) << "Removal of cryptohome for " << user_id.GetUserEmail()
                << " failed, return code: " << return_code;
   }
 }
@@ -117,12 +117,12 @@ bool UserMatches(const UserID& user_id, const base::DictionaryValue& dict) {
   std::string value;
 
   bool has_email = dict.GetString(kCanonicalEmail, &value);
-  if (has_email && user_id == value)
+  if (has_email && user_id == UserID::FromUserEmail(value))
     return true;
 
   // TODO(antrim): update code once user id is really a struct.
   bool has_gaia_id = dict.GetString(kGAIAIdKey, &value);
-  if (has_gaia_id && user_id == value)
+  if (has_gaia_id && user_id.GetGaiaId() == value)
     return true;
 
   return false;
@@ -130,7 +130,7 @@ bool UserMatches(const UserID& user_id, const base::DictionaryValue& dict) {
 
 // Fills relevant |dict| values based on |user_id|.
 void UpdateIdentity(const UserID& user_id, base::DictionaryValue& dict) {
-  dict.SetString(kCanonicalEmail, user_id);
+  dict.SetString(kCanonicalEmail, user_id.GetUserEmail());
 }
 
 }  // namespace
@@ -160,7 +160,10 @@ UserManagerBase::UserManagerBase(
       is_current_user_new_(false),
       is_current_user_ephemeral_regular_user_(false),
       ephemeral_users_enabled_(false),
+      owner_id_(std::string(), std::string()),
       manager_creation_time_(base::TimeTicks::Now()),
+      pending_user_switch_(std::string(), std::string()),
+      last_session_active_user_(std::string(), std::string()),
       last_session_active_user_initialized_(false),
       task_runner_(task_runner),
       blocking_task_runner_(blocking_task_runner),
@@ -198,17 +201,17 @@ const UserList& UserManagerBase::GetLRULoggedInUsers() const {
   return lru_logged_in_users_;
 }
 
-const std::string& UserManagerBase::GetOwnerEmail() const {
-  return owner_email_;
+const UserID& UserManagerBase::GetOwnerID() const {
+  return owner_id_;
 }
 
-void UserManagerBase::UserLoggedIn(const std::string& user_id,
+void UserManagerBase::UserLoggedIn(const UserID& user_id,
                                    const std::string& username_hash,
                                    bool browser_restart) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
   if (!last_session_active_user_initialized_) {
-    last_session_active_user_ = GetLocalState()->GetString(kLastActiveUser);
+    last_session_active_user_ = UserID::FromUserEmail(GetLocalState()->GetString(kLastActiveUser));
     last_session_active_user_initialized_ = true;
   }
 
@@ -226,10 +229,10 @@ void UserManagerBase::UserLoggedIn(const std::string& user_id,
     return;
   }
 
-  if (user_id == chromeos::login::kGuestUserName) {
+  if (user_id == chromeos::login::GetGuestUserID()) {
     GuestUserLoggedIn();
   } else if (IsKioskApp(user_id)) {
-    KioskAppLoggedIn(user_id);
+    KioskAppLoggedIn(user_id.GetUserEmail());
   } else if (IsDemoApp(user_id)) {
     DemoAccountLoggedIn();
   } else {
@@ -239,12 +242,12 @@ void UserManagerBase::UserLoggedIn(const std::string& user_id,
       PublicAccountUserLoggedIn(user);
     } else if ((user && user->GetType() == USER_TYPE_SUPERVISED) ||
                (!user &&
-                gaia::ExtractDomainName(user_id) ==
+                gaia::ExtractDomainName(user_id.GetUserEmail()) ==
                     chromeos::login::kSupervisedUserDomain)) {
       SupervisedUserLoggedIn(user_id);
     } else if (browser_restart && IsPublicAccountMarkedForRemoval(user_id)) {
       PublicAccountUserLoggedIn(User::CreatePublicAccountUser(user_id));
-    } else if (user_id != GetOwnerEmail() && !user &&
+    } else if (user_id != owner_id_ && !user &&
                (AreEphemeralUsersEnabled() || browser_restart)) {
       RegularUserLoggedInAsEphemeral(user_id);
     } else {
@@ -271,13 +274,13 @@ void UserManagerBase::UserLoggedIn(const std::string& user_id,
       "UserManager.LoginUserType", active_user_->GetType(), NUM_USER_TYPES);
 
   GetLocalState()->SetString(
-      kLastLoggedInGaiaUser, active_user_->HasGaiaAccount() ? user_id : "");
+      kLastLoggedInGaiaUser, active_user_->HasGaiaAccount() ? user_id.GetUserEmail() : "");
 
   NotifyOnLogin();
   PerformPostUserLoggedInActions(browser_restart);
 }
 
-void UserManagerBase::SwitchActiveUser(const std::string& user_id) {
+void UserManagerBase::SwitchActiveUser(const UserID& user_id) {
   User* user = FindUserAndModify(user_id);
   if (!user) {
     NOTREACHED() << "Switching to a non-existing user";
@@ -317,7 +320,7 @@ void UserManagerBase::SwitchToLastActiveUser() {
   if (last_session_active_user_.empty())
     return;
 
-  if (GetActiveUser()->email() != last_session_active_user_)
+  if (GetActiveUser()->GetUserID() != last_session_active_user_)
     SwitchActiveUser(last_session_active_user_);
 
   // Make sure that this function gets run only once.
@@ -338,7 +341,7 @@ void UserManagerBase::SessionStarted() {
   }
 }
 
-void UserManagerBase::RemoveUser(const std::string& user_id,
+void UserManagerBase::RemoveUser(const UserID& user_id,
                                  RemoveUserDelegate* delegate) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
@@ -348,36 +351,36 @@ void UserManagerBase::RemoveUser(const std::string& user_id,
   RemoveUserInternal(user_id, delegate);
 }
 
-void UserManagerBase::RemoveUserInternal(const std::string& user_email,
+void UserManagerBase::RemoveUserInternal(const UserID& user_id,
                                          RemoveUserDelegate* delegate) {
-  RemoveNonOwnerUserInternal(user_email, delegate);
+  RemoveNonOwnerUserInternal(user_id, delegate);
 }
 
-void UserManagerBase::RemoveNonOwnerUserInternal(const std::string& user_email,
+void UserManagerBase::RemoveNonOwnerUserInternal(const UserID& user_id,
                                                  RemoveUserDelegate* delegate) {
   if (delegate)
-    delegate->OnBeforeUserRemoved(user_email);
-  RemoveUserFromList(user_email);
+    delegate->OnBeforeUserRemoved(user_id);
+  RemoveUserFromList(user_id);
   cryptohome::AsyncMethodCaller::GetInstance()->AsyncRemove(
-      user_email, base::Bind(&OnRemoveUserComplete, user_email));
+      user_id, base::Bind(&OnRemoveUserComplete, user_id));
 
   if (delegate)
-    delegate->OnUserRemoved(user_email);
+    delegate->OnUserRemoved(user_id);
 }
 
-void UserManagerBase::RemoveUserFromList(const std::string& user_id) {
+void UserManagerBase::RemoveUserFromList(const UserID& user_id) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   RemoveNonCryptohomeData(user_id);
   if (user_loading_stage_ == STAGE_LOADED) {
     DeleteUser(RemoveRegularOrSupervisedUserFromList(user_id));
   } else if (user_loading_stage_ == STAGE_LOADING) {
-    DCHECK(gaia::ExtractDomainName(user_id) ==
+    DCHECK(gaia::ExtractDomainName(user_id.GetUserEmail()) ==
                chromeos::login::kSupervisedUserDomain ||
            HasPendingBootstrap(user_id));
     // Special case, removing partially-constructed supervised user or
     // boostrapping user during user list loading.
     ListPrefUpdate users_update(GetLocalState(), kRegularUsers);
-    users_update->Remove(base::StringValue(user_id), NULL);
+    users_update->Remove(base::StringValue(user_id.GetUserEmail()), NULL);
   } else {
     NOTREACHED() << "Users are not loaded yet.";
     return;
@@ -387,20 +390,20 @@ void UserManagerBase::RemoveUserFromList(const std::string& user_id) {
   GetLocalState()->CommitPendingWrite();
 }
 
-bool UserManagerBase::IsKnownUser(const std::string& user_id) const {
+bool UserManagerBase::IsKnownUser(const UserID& user_id) const {
   return FindUser(user_id) != NULL;
 }
 
-const User* UserManagerBase::FindUser(const std::string& user_id) const {
+const User* UserManagerBase::FindUser(const UserID& user_id) const {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
-  if (active_user_ && active_user_->email() == user_id)
+  if (active_user_ && active_user_->GetUserID() == user_id)
     return active_user_;
   return FindUserInList(user_id);
 }
 
-User* UserManagerBase::FindUserAndModify(const std::string& user_id) {
+User* UserManagerBase::FindUserAndModify(const UserID& user_id) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
-  if (active_user_ && active_user_->email() == user_id)
+  if (active_user_ && active_user_->GetUserID() == user_id)
     return active_user_;
   return FindUserInListAndModify(user_id);
 }
@@ -431,7 +434,7 @@ const User* UserManagerBase::GetPrimaryUser() const {
 }
 
 void UserManagerBase::SaveUserOAuthStatus(
-    const std::string& user_id,
+    const UserID& user_id,
     User::OAuthTokenStatus oauth_token_status) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
@@ -448,11 +451,11 @@ void UserManagerBase::SaveUserOAuthStatus(
   DictionaryPrefUpdate oauth_status_update(GetLocalState(),
                                            kUserOAuthTokenStatus);
   oauth_status_update->SetWithoutPathExpansion(
-      user_id,
+      user_id.GetUserEmail(),
       new base::FundamentalValue(static_cast<int>(oauth_token_status)));
 }
 
-void UserManagerBase::SaveForceOnlineSignin(const std::string& user_id,
+void UserManagerBase::SaveForceOnlineSignin(const UserID& user_id,
                                             bool force_online_signin) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
@@ -463,11 +466,11 @@ void UserManagerBase::SaveForceOnlineSignin(const std::string& user_id,
 
   DictionaryPrefUpdate force_online_update(GetLocalState(),
                                            kUserForceOnlineSignin);
-  force_online_update->SetBooleanWithoutPathExpansion(user_id,
+  force_online_update->SetBooleanWithoutPathExpansion(user_id.GetUserEmail(),
                                                       force_online_signin);
 }
 
-void UserManagerBase::SaveUserDisplayName(const std::string& user_id,
+void UserManagerBase::SaveUserDisplayName(const UserID& user_id,
                                           const base::string16& display_name) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
@@ -480,24 +483,24 @@ void UserManagerBase::SaveUserDisplayName(const std::string& user_id,
       DictionaryPrefUpdate display_name_update(GetLocalState(),
                                                kUserDisplayName);
       display_name_update->SetWithoutPathExpansion(
-          user_id, new base::StringValue(display_name));
+          user_id.GetUserEmail(), new base::StringValue(display_name));
     }
   }
 }
 
 base::string16 UserManagerBase::GetUserDisplayName(
-    const std::string& user_id) const {
+    const UserID& user_id) const {
   const User* user = FindUser(user_id);
   return user ? user->display_name() : base::string16();
 }
 
-void UserManagerBase::SaveUserDisplayEmail(const std::string& user_id,
+void UserManagerBase::SaveUserDisplayEmail(const UserID& user_id,
                                            const std::string& display_email) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
   User* user = FindUserAndModify(user_id);
   if (!user) {
-    LOG(ERROR) << "User not found: " << user_id;
+    LOG(ERROR) << "User not found: " << user_id.GetUserEmail();
     return;  // Ignore if there is no such user.
   }
 
@@ -510,22 +513,22 @@ void UserManagerBase::SaveUserDisplayEmail(const std::string& user_id,
 
   DictionaryPrefUpdate display_email_update(GetLocalState(), kUserDisplayEmail);
   display_email_update->SetWithoutPathExpansion(
-      user_id, new base::StringValue(display_email));
+      user_id.GetUserEmail(), new base::StringValue(display_email));
 }
 
 std::string UserManagerBase::GetUserDisplayEmail(
-    const std::string& user_id) const {
+    const UserID& user_id) const {
   const User* user = FindUser(user_id);
-  return user ? user->display_email() : user_id;
+  return user ? user->display_email() : user_id.GetUserEmail();
 }
 
-void UserManagerBase::SaveUserType(const std::string& user_id,
+void UserManagerBase::SaveUserType(const UserID& user_id,
                                    const UserType& user_type) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
   User* user = FindUserAndModify(user_id);
   if (!user) {
-    LOG(ERROR) << "User not found: " << user_id;
+    LOG(ERROR) << "User not found: " << user_id.GetUserEmail();
     return;  // Ignore if there is no such user.
   }
 
@@ -536,34 +539,34 @@ void UserManagerBase::SaveUserType(const std::string& user_id,
 
   DictionaryPrefUpdate user_type_update(GetLocalState(), kUserType);
   user_type_update->SetWithoutPathExpansion(
-      user_id, new base::FundamentalValue(static_cast<int>(user_type)));
+      user_id.GetUserEmail(), new base::FundamentalValue(static_cast<int>(user_type)));
   GetLocalState()->CommitPendingWrite();
 }
 
-void UserManagerBase::UpdateUsingSAML(const std::string& user_id,
+void UserManagerBase::UpdateUsingSAML(const UserID& user_id,
                                       const bool using_saml) {
   SetKnownUserBooleanPref(user_id, kUsingSAMLKey, using_saml);
 }
 
-bool UserManagerBase::FindUsingSAML(const std::string& user_id) {
+bool UserManagerBase::FindUsingSAML(const UserID& user_id) {
   bool using_saml;
   if (GetKnownUserBooleanPref(user_id, kUsingSAMLKey, &using_saml))
     return using_saml;
   return false;
 }
 
-void UserManagerBase::UpdateReauthReason(const std::string& user_id,
+void UserManagerBase::UpdateReauthReason(const UserID& user_id,
                                          const int reauth_reason) {
   SetKnownUserIntegerPref(user_id, kReauthReasonKey, reauth_reason);
 }
 
-bool UserManagerBase::FindReauthReason(const std::string& user_id,
+bool UserManagerBase::FindReauthReason(const UserID& user_id,
                                        int* out_value) {
   return GetKnownUserIntegerPref(user_id, kReauthReasonKey, out_value);
 }
 
 void UserManagerBase::UpdateUserAccountData(
-    const std::string& user_id,
+    const UserID& user_id,
     const UserAccountData& account_data) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
@@ -575,7 +578,7 @@ void UserManagerBase::UpdateUserAccountData(
     if (!IsUserNonCryptohomeDataEphemeral(user_id)) {
       DictionaryPrefUpdate given_name_update(GetLocalState(), kUserGivenName);
       given_name_update->SetWithoutPathExpansion(
-          user_id, new base::StringValue(given_name));
+          user_id.GetUserEmail(), new base::StringValue(given_name));
     }
   }
 
@@ -627,7 +630,7 @@ bool UserManagerBase::IsCurrentUserNew() const {
 bool UserManagerBase::IsCurrentUserNonCryptohomeDataEphemeral() const {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   return IsUserLoggedIn() &&
-         IsUserNonCryptohomeDataEphemeral(GetLoggedInUser()->email());
+         IsUserNonCryptohomeDataEphemeral(GetLoggedInUser()->GetUserID());
 }
 
 bool UserManagerBase::CanCurrentUserLock() const {
@@ -674,7 +677,7 @@ bool UserManagerBase::IsLoggedInAsKioskApp() const {
 bool UserManagerBase::IsLoggedInAsStub() const {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   return IsUserLoggedIn() &&
-         active_user_->email() == chromeos::login::kStubUser;
+         active_user_->GetUserID() == chromeos::login::GetStubUserID();
 }
 
 bool UserManagerBase::IsSessionStarted() const {
@@ -683,16 +686,16 @@ bool UserManagerBase::IsSessionStarted() const {
 }
 
 bool UserManagerBase::IsUserNonCryptohomeDataEphemeral(
-    const std::string& user_id) const {
+    const UserID& user_id) const {
   // Data belonging to the guest and stub users is always ephemeral.
-  if (user_id == chromeos::login::kGuestUserName ||
-      user_id == chromeos::login::kStubUser) {
+  if (user_id == chromeos::login::GetGuestUserID() ||
+      user_id == chromeos::login::GetStubUserID()) {
     return true;
   }
 
   // Data belonging to the owner, anyone found on the user list and obsolete
   // public accounts whose data has not been removed yet is not ephemeral.
-  if (user_id == GetOwnerEmail() || UserExistsInList(user_id) ||
+  if (user_id == owner_id_ || UserExistsInList(user_id) ||
       IsPublicAccountMarkedForRemoval(user_id)) {
     return false;
   }
@@ -702,7 +705,7 @@ bool UserManagerBase::IsUserNonCryptohomeDataEphemeral(
   //    policy was enabled.
   //    - or -
   // b) The user logged into any other account type.
-  if (IsUserLoggedIn() && (user_id == GetLoggedInUser()->email()) &&
+  if (IsUserLoggedIn() && (user_id == GetLoggedInUser()->GetUserID()) &&
       (is_current_user_ephemeral_regular_user_ ||
        !IsLoggedInAsUserWithGaiaAccount())) {
     return true;
@@ -763,7 +766,7 @@ bool UserManagerBase::CanUserBeRemoved(const User* user) const {
   for (UserList::const_iterator it = logged_in_users_.begin();
        it != logged_in_users_.end();
        ++it) {
-    if ((*it)->email() == user->email())
+    if ((*it)->GetUserID() == user->GetUserID())
       return false;
   }
 
@@ -782,19 +785,19 @@ void UserManagerBase::SetIsCurrentUserNew(bool is_new) {
   is_current_user_new_ = is_new;
 }
 
-bool UserManagerBase::HasPendingBootstrap(const std::string& user_id) const {
+bool UserManagerBase::HasPendingBootstrap(const UserID& user_id) const {
   return false;
 }
 
-void UserManagerBase::SetOwnerEmail(std::string owner_user_id) {
-  owner_email_ = owner_user_id;
+void UserManagerBase::SetOwnerID(const UserID& owner_user_id) {
+  owner_id_ = owner_user_id;
 }
 
-const std::string& UserManagerBase::GetPendingUserSwitchID() const {
+const user_manager::UserID& UserManagerBase::GetPendingUserSwitchID() const {
   return pending_user_switch_;
 }
 
-void UserManagerBase::SetPendingUserSwitchID(std::string user_id) {
+void UserManagerBase::SetPendingUserSwitchID(const user_manager::UserID& user_id) {
   pending_user_switch_ = user_id;
 }
 
@@ -837,20 +840,21 @@ void UserManagerBase::EnsureUsersLoaded() {
        it != regular_users.end();
        ++it) {
     User* user = NULL;
+    const UserID user_id(UserID::FromUserEmail(*it));
     const std::string domain = gaia::ExtractDomainName(*it);
     if (domain == chromeos::login::kSupervisedUserDomain) {
-      user = User::CreateSupervisedUser(*it);
+      user = User::CreateSupervisedUser(user_id);
     } else {
-      user = User::CreateRegularUser(*it);
+      user = User::CreateRegularUser(user_id);
       int user_type;
       if (prefs_user_types->GetIntegerWithoutPathExpansion(*it, &user_type) &&
           user_type == USER_TYPE_CHILD) {
         ChangeUserChildStatus(user, true /* is child */);
       }
     }
-    user->set_oauth_token_status(LoadUserOAuthStatus(*it));
-    user->set_force_online_signin(LoadForceOnlineSignin(*it));
-    user->set_using_saml(FindUsingSAML(*it));
+    user->set_oauth_token_status(LoadUserOAuthStatus(user_id));
+    user->set_force_online_signin(LoadForceOnlineSignin(user_id));
+    user->set_using_saml(FindUsingSAML(user_id));
     users_.push_back(user);
 
     base::string16 display_name;
@@ -881,29 +885,29 @@ UserList& UserManagerBase::GetUsersAndModify() {
   return users_;
 }
 
-const User* UserManagerBase::FindUserInList(const std::string& user_id) const {
+const User* UserManagerBase::FindUserInList(const UserID& user_id) const {
   const UserList& users = GetUsers();
   for (UserList::const_iterator it = users.begin(); it != users.end(); ++it) {
-    if ((*it)->email() == user_id)
+    if ((*it)->GetUserID() == user_id)
       return *it;
   }
   return NULL;
 }
 
-bool UserManagerBase::UserExistsInList(const std::string& user_id) const {
+bool UserManagerBase::UserExistsInList(const UserID& user_id) const {
   const base::ListValue* user_list = GetLocalState()->GetList(kRegularUsers);
   for (size_t i = 0; i < user_list->GetSize(); ++i) {
     std::string email;
-    if (user_list->GetString(i, &email) && (user_id == email))
+    if (user_list->GetString(i, &email) && (user_id == UserID::FromUserEmail(email)))
       return true;
   }
   return false;
 }
 
-User* UserManagerBase::FindUserInListAndModify(const std::string& user_id) {
+User* UserManagerBase::FindUserInListAndModify(const UserID& user_id) {
   UserList& users = GetUsersAndModify();
   for (UserList::iterator it = users.begin(); it != users.end(); ++it) {
-    if ((*it)->email() == user_id)
+    if ((*it)->GetUserID() == user_id)
       return *it;
   }
   return NULL;
@@ -917,11 +921,11 @@ void UserManagerBase::GuestUserLoggedIn() {
 void UserManagerBase::AddUserRecord(User* user) {
   // Add the user to the front of the user list.
   ListPrefUpdate prefs_users_update(GetLocalState(), kRegularUsers);
-  prefs_users_update->Insert(0, new base::StringValue(user->email()));
+  prefs_users_update->Insert(0, new base::StringValue(user->GetUserID().GetUserEmail()));
   users_.insert(users_.begin(), user);
 }
 
-void UserManagerBase::RegularUserLoggedIn(const std::string& user_id) {
+void UserManagerBase::RegularUserLoggedIn(const UserID& user_id) {
   // Remove the user from the user list.
   active_user_ = RemoveRegularOrSupervisedUserFromList(user_id);
 
@@ -930,7 +934,7 @@ void UserManagerBase::RegularUserLoggedIn(const std::string& user_id) {
   if (IsCurrentUserNew()) {
     active_user_ = User::CreateRegularUser(user_id);
     active_user_->set_oauth_token_status(LoadUserOAuthStatus(user_id));
-    SaveUserDisplayName(active_user_->email(),
+    SaveUserDisplayName(active_user_->GetUserID(),
                         base::UTF8ToUTF16(active_user_->GetAccountName(true)));
   }
 
@@ -941,7 +945,7 @@ void UserManagerBase::RegularUserLoggedIn(const std::string& user_id) {
 }
 
 void UserManagerBase::RegularUserLoggedInAsEphemeral(
-    const std::string& user_id) {
+    const UserID& user_id) {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   SetIsCurrentUserNew(true);
   is_current_user_ephemeral_regular_user_ = true;
@@ -957,14 +961,14 @@ void UserManagerBase::NotifyOnLogin() {
 }
 
 User::OAuthTokenStatus UserManagerBase::LoadUserOAuthStatus(
-    const std::string& user_id) const {
+    const UserID& user_id) const {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
   const base::DictionaryValue* prefs_oauth_status =
       GetLocalState()->GetDictionary(kUserOAuthTokenStatus);
   int oauth_token_status = User::OAUTH_TOKEN_STATUS_UNKNOWN;
   if (prefs_oauth_status &&
-      prefs_oauth_status->GetIntegerWithoutPathExpansion(user_id,
+      prefs_oauth_status->GetIntegerWithoutPathExpansion(user_id.GetUserEmail(),
                                                          &oauth_token_status)) {
     User::OAuthTokenStatus status =
         static_cast<User::OAuthTokenStatus>(oauth_token_status);
@@ -975,40 +979,40 @@ User::OAuthTokenStatus UserManagerBase::LoadUserOAuthStatus(
   return User::OAUTH_TOKEN_STATUS_UNKNOWN;
 }
 
-bool UserManagerBase::LoadForceOnlineSignin(const std::string& user_id) const {
+bool UserManagerBase::LoadForceOnlineSignin(const UserID& user_id) const {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
   const base::DictionaryValue* prefs_force_online =
       GetLocalState()->GetDictionary(kUserForceOnlineSignin);
   bool force_online_signin = false;
   if (prefs_force_online) {
-    prefs_force_online->GetBooleanWithoutPathExpansion(user_id,
+    prefs_force_online->GetBooleanWithoutPathExpansion(user_id.GetUserEmail(),
                                                        &force_online_signin);
   }
   return force_online_signin;
 }
 
-void UserManagerBase::RemoveNonCryptohomeData(const std::string& user_id) {
+void UserManagerBase::RemoveNonCryptohomeData(const UserID& user_id) {
   PrefService* prefs = GetLocalState();
   DictionaryPrefUpdate prefs_display_name_update(prefs, kUserDisplayName);
-  prefs_display_name_update->RemoveWithoutPathExpansion(user_id, NULL);
+  prefs_display_name_update->RemoveWithoutPathExpansion(user_id.GetUserEmail(), NULL);
 
   DictionaryPrefUpdate prefs_given_name_update(prefs, kUserGivenName);
-  prefs_given_name_update->RemoveWithoutPathExpansion(user_id, NULL);
+  prefs_given_name_update->RemoveWithoutPathExpansion(user_id.GetUserEmail(), NULL);
 
   DictionaryPrefUpdate prefs_display_email_update(prefs, kUserDisplayEmail);
-  prefs_display_email_update->RemoveWithoutPathExpansion(user_id, NULL);
+  prefs_display_email_update->RemoveWithoutPathExpansion(user_id.GetUserEmail(), NULL);
 
   DictionaryPrefUpdate prefs_oauth_update(prefs, kUserOAuthTokenStatus);
-  prefs_oauth_update->RemoveWithoutPathExpansion(user_id, NULL);
+  prefs_oauth_update->RemoveWithoutPathExpansion(user_id.GetUserEmail(), NULL);
 
   DictionaryPrefUpdate prefs_force_online_update(prefs, kUserForceOnlineSignin);
-  prefs_force_online_update->RemoveWithoutPathExpansion(user_id, NULL);
+  prefs_force_online_update->RemoveWithoutPathExpansion(user_id.GetUserEmail(), NULL);
 
   RemoveKnownUserPrefs(user_id);
 
-  std::string last_active_user = GetLocalState()->GetString(kLastActiveUser);
-  if (user_id == last_active_user)
+  const std::string last_active_user = GetLocalState()->GetString(kLastActiveUser);
+  if (user_id == UserID::FromUserEmail(last_active_user))
     GetLocalState()->SetString(kLastActiveUser, std::string());
 }
 
@@ -1164,18 +1168,17 @@ std::string UserManagerBase::GetKnownUserDeviceId(const UserID& user_id) {
 }
 
 User* UserManagerBase::RemoveRegularOrSupervisedUserFromList(
-    const std::string& user_id) {
+    const UserID& user_id) {
   ListPrefUpdate prefs_users_update(GetLocalState(), kRegularUsers);
   prefs_users_update->Clear();
   User* user = NULL;
   for (UserList::iterator it = users_.begin(); it != users_.end();) {
-    const std::string user_email = (*it)->email();
-    if (user_email == user_id) {
+    if ((*it)->GetUserID() == user_id) {
       user = *it;
       it = users_.erase(it);
     } else {
       if ((*it)->HasGaiaAccount() || (*it)->IsSupervised())
-        prefs_users_update->Append(new base::StringValue(user_email));
+        prefs_users_update->Append(new base::StringValue((*it)->GetUserID().GetUserEmail()));
       ++it;
     }
   }
@@ -1222,7 +1225,7 @@ void UserManagerBase::ChangeUserChildStatus(User* user, bool is_child) {
   if (user->IsSupervised() == is_child)
     return;
   user->SetIsChild(is_child);
-  SaveUserType(user->email(), is_child ? user_manager::USER_TYPE_CHILD
+  SaveUserType(user->GetUserID(), is_child ? user_manager::USER_TYPE_CHILD
                                        : user_manager::USER_TYPE_REGULAR);
   FOR_EACH_OBSERVER(UserManager::UserSessionStateObserver,
                     session_state_observer_list_,
@@ -1263,7 +1266,7 @@ void UserManagerBase::UpdateLoginState() {
 }
 
 void UserManagerBase::SetLRUUser(User* user) {
-  GetLocalState()->SetString(kLastActiveUser, user->email());
+  GetLocalState()->SetString(kLastActiveUser, user->GetUserID().GetUserEmail());
   GetLocalState()->CommitPendingWrite();
 
   UserList::iterator it =
@@ -1273,7 +1276,7 @@ void UserManagerBase::SetLRUUser(User* user) {
   lru_logged_in_users_.insert(lru_logged_in_users_.begin(), user);
 }
 
-void UserManagerBase::SendGaiaUserLoginMetrics(const std::string& user_id) {
+void UserManagerBase::SendGaiaUserLoginMetrics(const UserID& user_id) {
   // If this isn't the first time Chrome was run after the system booted,
   // assume that Chrome was restarted because a previous session ended.
   if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
@@ -1282,7 +1285,7 @@ void UserManagerBase::SendGaiaUserLoginMetrics(const std::string& user_id) {
         GetLocalState()->GetString(kLastLoggedInGaiaUser);
     const base::TimeDelta time_to_login =
         base::TimeTicks::Now() - manager_creation_time_;
-    if (!last_email.empty() && user_id != last_email &&
+    if (!last_email.empty() && user_id != UserID::FromUserEmail(last_email) &&
         time_to_login.InSeconds() <= kLogoutToLoginDelayMaxSec) {
       UMA_HISTOGRAM_CUSTOM_COUNTS("UserManager.LogoutToLoginDelay",
                                   time_to_login.InSeconds(),
@@ -1293,7 +1296,7 @@ void UserManagerBase::SendGaiaUserLoginMetrics(const std::string& user_id) {
   }
 }
 
-void UserManagerBase::UpdateUserAccountLocale(const std::string& user_id,
+void UserManagerBase::UpdateUserAccountLocale(const UserID& user_id,
                                               const std::string& locale) {
   scoped_ptr<std::string> resolved_locale(new std::string());
   if (!locale.empty() && locale != GetApplicationLocale()) {
@@ -1315,7 +1318,7 @@ void UserManagerBase::UpdateUserAccountLocale(const std::string& user_id,
 }
 
 void UserManagerBase::DoUpdateAccountLocale(
-    const std::string& user_id,
+    const UserID& user_id,
     scoped_ptr<std::string> resolved_locale) {
   User* user = FindUserAndModify(user_id);
   if (user && resolved_locale)