This CL replaces user_manager::UserID with AccountId.

chrome/browser/chromeos/login/supervised/supervised_user_authentication.cc

Index: chrome/browser/chromeos/login/supervised/supervised_user_authentication.cc
diff --git a/chrome/browser/chromeos/login/supervised/supervised_user_authentication.cc b/chrome/browser/chromeos/login/supervised/supervised_user_authentication.cc
index 74856040c8920487340ed91e96a340a85f126cd4..fedc5ae8f796d138bbc1db93ec975398b07006c2 100644
--- a/chrome/browser/chromeos/login/supervised/supervised_user_authentication.cc
+++ b/chrome/browser/chromeos/login/supervised/supervised_user_authentication.cc
@@ -104,14 +104,14 @@ SupervisedUserAuthentication::GetStableSchema() {
 UserContext SupervisedUserAuthentication::TransformKey(
     const UserContext& context) {
   UserContext result = context;
-  int user_schema = GetPasswordSchema(context.GetUserID());
+  int user_schema = GetPasswordSchema(context.GetUserID().GetUserEmail());
   if (user_schema == SCHEMA_PLAIN)
     return result;
 
   if (user_schema == SCHEMA_SALT_HASHED) {
     base::DictionaryValue holder;
     std::string salt;
-    owner_->GetPasswordInformation(context.GetUserID(), &holder);
+    owner_->GetPasswordInformation(context.GetUserID().GetUserEmail(), &holder);
     holder.GetStringWithoutPathExpansion(kSalt, &salt);
     DCHECK(!salt.empty());
     Key* const key = result.GetKey();
@@ -120,7 +120,8 @@ UserContext SupervisedUserAuthentication::TransformKey(
     result.SetIsUsingOAuth(false);
     return result;
   }
-  NOTREACHED() << "Unknown password schema for " << context.GetUserID();
+  NOTREACHED() << "Unknown password schema for "
+               << context.GetUserID().GetUserEmail();
   return context;
 }
 
@@ -223,8 +224,8 @@ bool SupervisedUserAuthentication::NeedPasswordChange(
 void SupervisedUserAuthentication::ScheduleSupervisedPasswordChange(
     const std::string& supervised_user_id,
     const base::DictionaryValue* password_data) {
-  const user_manager::User* user =
-      user_manager::UserManager::Get()->FindUser(supervised_user_id);
+  const user_manager::User* user = user_manager::UserManager::Get()->FindUser(
+      AccountId::FromUserEmail(supervised_user_id));
   base::FilePath profile_path = ProfileHelper::GetProfilePathByUserIdHash(
       user->username_hash());
   JSONFileValueSerializer serializer(profile_path.Append(kPasswordUpdateFile));
@@ -281,8 +282,8 @@ void SupervisedUserAuthentication::LoadPasswordUpdateData(
     const std::string& user_id,
     const PasswordDataCallback& success_callback,
     const base::Closure& failure_callback) {
-  const user_manager::User* user =
-      user_manager::UserManager::Get()->FindUser(user_id);
+  const user_manager::User* user = user_manager::UserManager::Get()->FindUser(
+      AccountId::FromUserEmail(user_id));
   base::FilePath profile_path =
       ProfileHelper::GetProfilePathByUserIdHash(user->username_hash());
   PostTaskAndReplyWithResult(