React to primary display change instead of removal

chrome/browser/ui/webui/chromeos/login/oobe_display_chooser_unittest.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 "chrome/browser/ui/webui/chromeos/login/oobe_display_chooser.h"
 
 #include <memory>
 
 #include "ash/display/display_configuration_controller.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
+#include "base/run_loop.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/display/display.h"
 #include "ui/display/display_observer.h"
 #include "ui/display/manager/display_manager.h"
 #include "ui/display/screen.h"
 #include "ui/display/test/display_manager_test_api.h"
 
 namespace chromeos {
 
 namespace {
@@ skipping 34 matching lines @@
 TEST_F(OobeDisplayChooserTest, PreferTouchAsPrimary) {
   OobeDisplayChooser display_chooser;
 
   UpdateDisplay("3000x2000,800x600");
   display::DisplayIdList ids = display_manager()->GetCurrentDisplayIdList();
   DisableTouch(ids[0]);
   EnableTouch(ids[1]);
 
   EXPECT_EQ(ids[0], GetPrimaryDisplay());
   display_chooser.TryToPlaceUiOnTouchDisplay();
+  base::RunLoop().RunUntilIdle();
 
   EXPECT_EQ(ids[1], GetPrimaryDisplay());
 }
 
 TEST_F(OobeDisplayChooserTest, AddingSecondTouchDisplayShouldbeNOP) {
   OobeDisplayChooser display_chooser;
 
   UpdateDisplay("3000x2000,800x600");
   display::DisplayIdList ids = display_manager()->GetCurrentDisplayIdList();
   EnableTouch(ids[0]);
   EnableTouch(ids[1]);
 
   EXPECT_EQ(ids[0], GetPrimaryDisplay());
   display_chooser.TryToPlaceUiOnTouchDisplay();
+  base::RunLoop().RunUntilIdle();
 
   EXPECT_EQ(ids[0], GetPrimaryDisplay());
 }
 
 }  // namespace chromeos