The User Manager should be backed by a special profile, not the guest one.

chrome/browser/profiles/profile_window.cc

Index: chrome/browser/profiles/profile_window.cc
diff --git a/chrome/browser/profiles/profile_window.cc b/chrome/browser/profiles/profile_window.cc
index f6ed167e2bff00de546b70efa87ad85b2a933baa..d0d023cd503e57a026520321f6f61df93e9cf34e 100644
--- a/chrome/browser/profiles/profile_window.cc
+++ b/chrome/browser/profiles/profile_window.cc
@@ -122,14 +122,14 @@ void OpenBrowserWindowForProfile(
       true);
 }
 
-// Called after a |guest_profile| is available to be used by the user manager.
+// Called after a |profile| is available to be used by the user manager.
 // Based on the value of |tutorial_mode| we determine a url to be displayed
 // by the webui and run the |callback|, if it exists.
-void OnUserManagerGuestProfileCreated(
+void OnUserManagerProfileCreated(
     const base::FilePath& profile_path_to_focus,
     profiles::UserManagerTutorialMode tutorial_mode,
     const base::Callback<void(Profile*, const std::string&)>& callback,
-    Profile* guest_profile,
+    Profile* profile,
     Profile::CreateStatus status) {
   if (status != Profile::CREATE_STATUS_INITIALIZED || callback.is_null())
     return;
@@ -149,7 +149,7 @@ void OnUserManagerGuestProfileCreated(
     }
   }
 
-  callback.Run(guest_profile, page);
+  callback.Run(profile, page);
 }
 
 }  // namespace
@@ -253,15 +253,15 @@ void LockProfile(Profile* profile) {
   BrowserList::CloseAllBrowsersWithProfile(profile);
 }
 
-void CreateGuestProfileForUserManager(
+void CreateUserManagerProfile(
     const base::FilePath& profile_path_to_focus,
     profiles::UserManagerTutorialMode tutorial_mode,
     const base::Callback<void(Profile*, const std::string&)>& callback) {
   // Create the guest profile, if necessary, and open the User Manager
   // from the guest profile.
   g_browser_process->profile_manager()->CreateProfileAsync(
-      ProfileManager::GetGuestProfilePath(),
-      base::Bind(&OnUserManagerGuestProfileCreated,
+      ProfileManager::GetUserManagerProfilePath(),
+      base::Bind(&OnUserManagerProfileCreated,
                  profile_path_to_focus,
                  tutorial_mode,
                  callback),