cros: Skip need-dircrypto-migration check if not needed

chrome/browser/chromeos/login/screens/user_selection_screen_browsertest.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <memory>
 #include <utility>
 
+#include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
 #include "chrome/browser/chromeos/login/login_manager_test.h"
 #include "chrome/browser/chromeos/login/startup_utils.h"
 #include "chrome/browser/chromeos/login/test/oobe_screen_waiter.h"
 #include "chrome/browser/ui/webui/chromeos/login/oobe_ui.h"
 #include "chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h"
+#include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/fake_cryptohome_client.h"
 
 namespace chromeos {
 
 namespace {
 
 constexpr char kTestUser1[] = "test-user1@gmail.com";
 constexpr char kTestUser2[] = "test-user2@gmail.com";
 
@@ skipping 30 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(UserSelectionScreenTest,
                        PRE_ShowDircryptoMigrationBanner) {
   RegisterUser(kTestUser1);
   RegisterUser(kTestUser2);
   StartupUtils::MarkOobeCompleted();
 }
 
 // Test that a banner shows up for users that need dircrypto migration.
 IN_PROC_BROWSER_TEST_F(UserSelectionScreenTest, ShowDircryptoMigrationBanner) {
+  // Enable ARC. Otherwise, the banner would not show.
+  base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
+      switches::kArcAvailability, "officially-supported");
+
   // No banner for the first user since default is no migration.
   JSExpect("!$('signin-banner').classList.contains('message-set')");
 
   // Change the needs dircrypto migration response.
   fake_cryptohome_client()->set_needs_dircrypto_migration(true);
 
   // Focus to the 2nd user pod.
   base::RunLoop pod_focus_wait_loop;
   GetOobeUI()->signin_screen_handler()->SetFocusPODCallbackForTesting(
       pod_focus_wait_loop.QuitClosure());
   js_checker().Evaluate("$('pod-row').focusPod($('pod-row').pods[1])");
   pod_focus_wait_loop.Run();
 
   // Wait for FakeCryptohomeClient to send back the check result.
   base::RunLoop().RunUntilIdle();
 
   // Banner should be shown for the 2nd user.
   JSExpect("$('signin-banner').classList.contains('message-set')");
 }
 
 }  // namespace chromeos