[cros] Fake a stub user login when no --login-manager and --login-user are given.

chrome/test/base/testing_profile.cc

Index: chrome/test/base/testing_profile.cc
diff --git a/chrome/test/base/testing_profile.cc b/chrome/test/base/testing_profile.cc
index f55347f6b56d2cadbddf95cdc90cf724dbb63692..2431224771c80f0de1723ad89655c22125378f6f 100644
--- a/chrome/test/base/testing_profile.cc
+++ b/chrome/test/base/testing_profile.cc
@@ -143,6 +143,15 @@ ProfileKeyedService* CreateTestDesktopNotificationService(Profile* profile) {
 
 }  // namespace
 
+// static
+#if defined(OS_CHROMEOS)
+// Must be kept in sync with
+// ChromeBrowserMainPartsChromeos::PreEarlyInitialization.
+const char TestingProfile::kTestUserProfileDir[] = "test-user";
+#else
+const char TestingProfile::kTestUserProfileDir[] = "Default";
+#endif
+
 TestingProfile::TestingProfile()
     : start_time_(Time::Now()),
       testing_prefs_(NULL),