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

chrome/browser/profiles/profile_manager_unittest.cc

Index: chrome/browser/profiles/profile_manager_unittest.cc
diff --git a/chrome/browser/profiles/profile_manager_unittest.cc b/chrome/browser/profiles/profile_manager_unittest.cc
index 82e8fd9eb80abbd82c67aa9490141b774d0a3eed..c529a8147cdf500053afa03592c0dfd0cafa520c 100644
--- a/chrome/browser/profiles/profile_manager_unittest.cc
+++ b/chrome/browser/profiles/profile_manager_unittest.cc
@@ -357,10 +357,17 @@ TEST_F(ProfileManagerTest, AddProfileToCacheCheckOmitted) {
 TEST_F(ProfileManagerTest, GetGuestProfilePath) {
   base::FilePath guest_path = ProfileManager::GetGuestProfilePath();
   base::FilePath expected_path = temp_dir_.path();
-  expected_path = expected_path.Append(chrome::kGuestProfileDir);
+  expected_path = expected_path.AppendASCII(chrome::kGuestProfileDir);
   EXPECT_EQ(expected_path, guest_path);
 }
 
+TEST_F(ProfileManagerTest, GetUserManagerProfilePath) {
+  base::FilePath path = ProfileManager::GetUserManagerProfilePath();
+  base::FilePath expected_path = temp_dir_.path();
+  expected_path = expected_path.AppendASCII(chrome::kUserManagerProfileDir);
+  EXPECT_EQ(expected_path, path);
+}
+
 class UnittestGuestProfileManager : public UnittestProfileManager {
  public:
   explicit UnittestGuestProfileManager(const base::FilePath& user_data_dir)