ChromeOS: fix user signin by alias.

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

Index: chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.cc
index 34c61120f6cc61fb28641bd50aa29d52c23725ff..6eda49e630cf2d46c4fb82191c8c7eaa1b716097 100644
--- a/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.cc
@@ -515,6 +515,28 @@ void GaiaScreenHandler::HandleWebviewLoadAborted(
   UpdateState(error_reason);
 }
 
+std::string GaiaScreenHandler::GetCanonicalEmail(
+    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);
+  user_manager::UserManager* user_manager = user_manager::UserManager::Get();
+  if (user_manager && !user_manager->IsKnownUser(canonicalized_email)) {
+    std::string old_email;
+    if (user_manager->GetKnownUserCanonicalEmail(gaia_id, &old_email)) {
+      if (old_email != canonicalized_email) {
+        LOG(WARNING) << "Existing user '" << old_email

[achuithb, 2015/09/29 18:18:42]

Should we make this LOG(INFO)?

Also, should we add UMA stats for this event?

[Alexander Alekseev, 2015/09/29 19:02:07]

LOG(INFO) is prohibited by precommit hooks.
So you think we should still use INFO?

[achuithb, 2015/09/29 19:07:48]

Doesn't feel like a WARNING, but I guess it's ok.

What about the UMA stat?

+                     << "' authenticated by alias '" << canonicalized_email
+                     << "'.";
+        return old_email;
+      }
+    }
+  }
+  return sanitized_email;

[achuithb, 2015/09/29 18:18:42]

The names are a bit confusing.

This method is called GetCanonicalEmail, you have variables, sanitized_email,
canonicalized_email, old_email, authenticated_email, gaia_id. What is the
difference between all of these? Could we add a comment somewhere?

[Alexander Alekseev, 2015/09/29 19:02:07]

It actually is returning sanitized email for compatibility.
We should probably call Canonicalize() here, but currently we rely on GAIA to
return canonical e-mail.

On the other hand, UserContext returns canonicalized e-mail, so that KnownUsers
data is stored using canonicalized e-mails as ID.

This way, it all works because Canonicalize() is done on GAIA side ;)

I've added comment here.

+}
+
 void GaiaScreenHandler::HandleCompleteAuthentication(
     const std::string& gaia_id,
     const std::string& email,
@@ -531,7 +553,9 @@ void GaiaScreenHandler::HandleCompleteAuthentication(
   DCHECK(!gaia_id.empty());
   const std::string sanitized_email = gaia::SanitizeEmail(email);
   Delegate()->SetDisplayEmail(sanitized_email);
-  UserContext user_context(sanitized_email);
+
+  const std::string canonical_email = GetCanonicalEmail(email, gaia_id);
+  UserContext user_context(canonical_email);
   user_context.SetGaiaID(gaia_id);
   user_context.SetKey(Key(password));
   user_context.SetAuthCode(auth_code);
@@ -657,7 +681,8 @@ void GaiaScreenHandler::DoCompleteLogin(const std::string& gaia_id,
   DCHECK(!gaia_id.empty());
   const std::string sanitized_email = gaia::SanitizeEmail(typed_email);
   Delegate()->SetDisplayEmail(sanitized_email);
-  UserContext user_context(sanitized_email);
+  const std::string canonical_email = GetCanonicalEmail(typed_email, gaia_id);
+  UserContext user_context(canonical_email);
   user_context.SetGaiaID(gaia_id);
   user_context.SetKey(Key(password));
   user_context.SetAuthFlow(using_saml