This CL replaces user_manager::UserID with AccountId.

chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.cc

 // Copyright 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/ui/webui/chromeos/login/gaia_screen_handler.h"
 
 #include "ash/system/chromeos/devicetype_utils.h"
 #include "base/bind.h"
 #include "base/guid.h"
 #include "base/logging.h"
@@ skipping 410 matching lines @@
   else
     frame_error_ = net::ERR_INTERNET_DISCONNECTED;
 
   LOG(ERROR) << "Gaia webview error: " << error_reason_str;
   NetworkError::ErrorReason error_reason =
       NetworkError::ERROR_REASON_FRAME_ERROR;
   frame_state_ = FRAME_STATE_ERROR;
   UpdateState(error_reason);
 }
 
-std::string GaiaScreenHandler::GetCanonicalEmail(
+AccountId GaiaScreenHandler::GetAccountId(
     const std::string& authenticated_email,
     const std::string& gaia_id) const {
   const std::string sanitized_email = gaia::SanitizeEmail(authenticated_email);
 
   const std::string canonicalized_email =
       gaia::CanonicalizeEmail(sanitized_email);
+  const AccountId authenticated_id(
+      AccountId::FromUserEmailGaiaId(canonicalized_email, gaia_id));
+
   user_manager::UserManager* user_manager = user_manager::UserManager::Get();
-  if (user_manager && !user_manager->IsKnownUser(canonicalized_email)) {
-    std::string old_canonical_email;
-    if (user_manager->GetKnownUserCanonicalEmail(gaia_id,
-                                                 &old_canonical_email)) {
-      if (old_canonical_email != canonicalized_email) {
-        LOG(WARNING) << "Existing user '" << old_canonical_email
+  if (user_manager && !user_manager->IsKnownUser(authenticated_id)) {

[stevenjb, 2015/10/22 17:52:36]

nit: invert and early exit

[Alexander Alekseev, 2015/10/23 09:11:23]

Done.

+    AccountId old_account_id(EmptyAccountId());

[stevenjb, 2015/10/22 17:52:36]

It looks like this ship has sailed, but it is a bit jarring to me to discover
that EmptyAccountId is in the global namespace. (I spent some time looking for
the local definition).

[Alexander Alekseev, 2015/10/23 09:11:23]

The reason for this is to make EmptyAccountId() look like other reserved 
account ids (like GuestAccountId(), etc...). At least for now.

Probably it would be better to allow AccountId to be default-constructible, but
it is dangerous while we are in transition. Once the transition is finished,
probably it would become just AccountId() .

+    if (user_manager->GetKnownUserAccountId(authenticated_id,
+                                            &old_account_id)) {

[stevenjb, 2015/10/22 17:52:36]

nit: invert and early exit (same below, maybe combine)

[Alexander Alekseev, 2015/10/23 09:11:23]

Done.

+      if (old_account_id.GetUserEmail() != canonicalized_email) {
+        LOG(WARNING) << "Existing user '" << old_account_id.GetUserEmail()
                      << "' authenticated by alias '" << sanitized_email << "'.";
-        return old_canonical_email;
+        return old_account_id;
       }
     }
   }
-  // For compatibility reasons, sanitized email is used.
-  return sanitized_email;
+  return authenticated_id;
 }
 
 void GaiaScreenHandler::HandleCompleteAuthentication(
     const std::string& gaia_id,
     const std::string& email,
     const std::string& password,
     const std::string& auth_code,
     bool using_saml,
     const std::string& gaps_cookie) {
   if (!Delegate())
     return;
 
   DCHECK(!email.empty());
   DCHECK(!gaia_id.empty());
   const std::string sanitized_email = gaia::SanitizeEmail(email);
   Delegate()->SetDisplayEmail(sanitized_email);
 
-  const std::string canonical_email = GetCanonicalEmail(email, gaia_id);
-  UserContext user_context(canonical_email);
+  const AccountId account_id(GetAccountId(email, gaia_id));
+  UserContext user_context(account_id);

[achuithb, 2015/10/23 00:08:51]

Just inline invocation to GetAccountId(email, gaia_id) here

[Alexander Alekseev, 2015/10/23 09:11:23]

Done.

   user_context.SetGaiaID(gaia_id);
   user_context.SetKey(Key(password));
   user_context.SetAuthCode(auth_code);
   user_context.SetAuthFlow(using_saml
                                ? UserContext::AUTH_FLOW_GAIA_WITH_SAML
                                : UserContext::AUTH_FLOW_GAIA_WITHOUT_SAML);
   user_context.SetGAPSCookie(gaps_cookie);
   Delegate()->CompleteLogin(user_context);
 }
 
@@ skipping 12 matching lines @@
                                             const std::string& typed_email,
                                             const std::string& password,
                                             bool using_saml) {
   if (!is_enrolling_consumer_management_) {
     DoCompleteLogin(gaia_id, typed_email, password, using_saml);
     return;
   }
 
   // Consumer management enrollment is in progress.
   const std::string owner_email =
-      user_manager::UserManager::Get()->GetOwnerEmail();
+      user_manager::UserManager::Get()->GetOwnerId().GetUserEmail();
   if (typed_email != owner_email) {
     // Show Gaia sign-in screen again, since we only allow the owner to sign
     // in.
     populated_email_ = owner_email;
     ShowGaiaAsync(is_enrolling_consumer_management_);
     return;
   }
 
   CHECK(consumer_management_);
   consumer_management_->SetOwner(owner_email,
@@ skipping 67 matching lines @@
   if (!Delegate())
     return;
 
   if (using_saml && !using_saml_api_)
     RecordSAMLScrapingVerificationResultInHistogram(true);
 
   DCHECK(!typed_email.empty());
   DCHECK(!gaia_id.empty());
   const std::string sanitized_email = gaia::SanitizeEmail(typed_email);
   Delegate()->SetDisplayEmail(sanitized_email);
-  const std::string canonical_email = GetCanonicalEmail(typed_email, gaia_id);
-  UserContext user_context(canonical_email);
+  const AccountId account_id(GetAccountId(typed_email, gaia_id));
+  UserContext user_context(account_id);

[achuithb, 2015/10/23 00:08:51]

inline GetAccountId

[Alexander Alekseev, 2015/10/23 09:11:23]

Done.

   user_context.SetGaiaID(gaia_id);
   user_context.SetKey(Key(password));
   user_context.SetAuthFlow(using_saml
                                ? UserContext::AUTH_FLOW_GAIA_WITH_SAML
                                : UserContext::AUTH_FLOW_GAIA_WITHOUT_SAML);
   Delegate()->CompleteLogin(user_context);
 
   if (test_expects_complete_login_) {
     VLOG(2) << "Complete test login for " << typed_email
             << ", requested=" << test_user_;
@@ skipping 138 matching lines @@
   imm->SetState(gaia_ime_state);
 
   // Set Least Recently Used input method for the user.
   if (!populated_email_.empty()) {
     SigninScreenHandler::SetUserInputMethod(populated_email_,
                                             gaia_ime_state.get());
   } else {
     std::vector<std::string> input_methods =
         imm->GetInputMethodUtil()->GetHardwareLoginInputMethodIds();
     const std::string owner_im = SigninScreenHandler::GetUserLRUInputMethod(
-        user_manager::UserManager::Get()->GetOwnerEmail());
+        user_manager::UserManager::Get()->GetOwnerId().GetUserEmail());
     const std::string system_im = g_browser_process->local_state()->GetString(
         language_prefs::kPreferredKeyboardLayout);
 
     PushFrontIMIfNotExists(owner_im, &input_methods);
     PushFrontIMIfNotExists(system_im, &input_methods);
 
     gaia_ime_state->EnableLoginLayouts(
         g_browser_process->GetApplicationLocale(), input_methods);
 
     if (!system_im.empty()) {
@@ skipping 67 matching lines @@
           << ", silent_load: " << silent_load
           << ", offline: " << offline;
   GaiaContext context;
   context.force_reload = force;
   context.is_local = offline;
   context.use_offline = offline;
   context.email = populated_email_;
   context.is_enrolling_consumer_management = is_enrolling_consumer_management_;
 
   std::string gaia_id;
-  if (user_manager::UserManager::Get()->FindGaiaID(context.email, &gaia_id))
+  if (user_manager::UserManager::Get()->FindGaiaID(
+          AccountId::FromUserEmail(context.email), &gaia_id))
     context.gaia_id = gaia_id;
 
   if (Delegate()) {
     context.show_users = Delegate()->IsShowUsers();
   }
 
   if (!context.email.empty()) {
     context.gaps_cookie =
         user_manager::UserManager::Get()->GetKnownUserGAPSCookie(
-            gaia::CanonicalizeEmail(context.email));
+            AccountId::FromUserEmail(gaia::CanonicalizeEmail(context.email)));
   }
 
   populated_email_.clear();
 
   LoadGaia(context);
 }
 
 void GaiaScreenHandler::UpdateState(NetworkError::ErrorReason reason) {
   if (signin_screen_handler_)
     signin_screen_handler_->UpdateState(reason);
@@ skipping 11 matching lines @@
              NetworkPortalDetector::CAPTIVE_PORTAL_STATUS_PORTAL ||
          captive_portal_status_ ==
              NetworkPortalDetector::CAPTIVE_PORTAL_STATUS_OFFLINE;
 }
 
 void GaiaScreenHandler::DisableRestrictiveProxyCheckForTest() {
   disable_restrictive_proxy_check_for_test_ = true;
 }
 
 }  // namespace chromeos