This CL replaces user_manager::UserID with AccountId.

chrome/browser/chromeos/app_mode/kiosk_app_manager.cc

Index: chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
diff --git a/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc b/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
index bb339fe9a7b6015f39417022a44d6b82e3cad454..0dd9f22d4899af80e0f9b633d8fb0c15b5a3beb8 100644
--- a/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
+++ b/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
@@ -38,6 +38,7 @@
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/settings/cros_settings_names.h"
 #include "components/ownership/owner_key_util.h"
+#include "components/signin/core/account_id/account_id.h"
 #include "components/user_manager/user_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "extensions/common/extension_urls.h"
@@ -640,9 +641,9 @@ void KioskAppManager::UpdateAppData() {
   const user_manager::User* active_user =
       user_manager::UserManager::Get()->GetActiveUser();
   if (active_user) {
-    std::string active_user_id = active_user->GetUserID();
+    const AccountId active_account_id = active_user->GetAccountId();
     for (const auto& it : old_apps) {
-      if (it.second->user_id() == active_user_id) {
+      if (it.second->user_id() == active_account_id.GetUserEmail()) {

[stevenjb, 2015/10/23 17:17:02]

Is GetUserEmail() just an accessor? If so, we should rename it user_mail() (in a
separate CL). If not, we should store it locally here instead of calling a
function for every app.

[Alexander Alekseev, 2015/10/23 23:21:22]

user_id must return AccountId (and it will shortly). So this is just a reminder,
that we need to drop GetUserEmail() here.

GetUserEmail() may stay as an accessor, or may become something complex. It has
specifically chosen name so that we could grep sources for it and find how many
files are still to be updated.

Actually, I expect GetUserEmail() to disappear at some moment.

[stevenjb, 2015/10/26 18:28:00]

So then, in case GetUserEmail doesn't get removed and ends up being something
non trivial, we should store it locally, i.e. 'std::string account_email =
active_account_id.GetUserEmail()'. But if we're definitely going to eliminate it
soon, I guess that is optional.

         VLOG(1) << "Currently running kiosk app removed from policy, exiting";
         cryptohomes_barrier_closure = BarrierClosure(
             old_apps.size(), base::Bind(&chrome::AttemptUserExit));