chromeos: Remove AshTestBase::SupportsMultipleDisplays

ash/mus/top_level_window_factory_unittest.cc

 // Copyright 2016 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 "ash/common/test/ash_test.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
 #include "ash/mus/test/wm_test_base.h"
 #include "ui/aura/window.h"
 #include "ui/display/screen.h"
@@ skipping 14 matching lines @@
   std::unique_ptr<WindowOwner> window_owner = CreateToplevelTestWindow();
   WmWindow* window = window_owner->window();
   window->SetFullscreen(true);
   WmWindow* root_window = WmShell::Get()->GetPrimaryRootWindow();
   EXPECT_EQ(root_window->GetBounds(), window->GetBounds());
 }
 
 using TopLevelWindowFactoryWmTest = mus::WmTestBase;
 
 TEST_F(TopLevelWindowFactoryWmTest, IsWindowShownInCorrectDisplay) {
-  if (!SupportsMultipleDisplays())
-    return;
-
   UpdateDisplay("400x400,400x400");
   EXPECT_NE(GetPrimaryDisplay().id(), GetSecondaryDisplay().id());
 
   std::unique_ptr<aura::Window> window_primary_display(
       CreateFullscreenTestWindow(GetPrimaryDisplay().id()));
   std::unique_ptr<aura::Window> window_secondary_display(
       CreateFullscreenTestWindow(GetSecondaryDisplay().id()));
 
   EXPECT_EQ(GetPrimaryDisplay().id(),
             GetDisplayId(window_primary_display.get()));
   EXPECT_EQ(GetSecondaryDisplay().id(),
             GetDisplayId(window_secondary_display.get()));
 }
 
 }  // namespace ash