chromeos: Remove AshTestBase::SupportsMultipleDisplays

ash/mus/test/ash_test_impl_mus.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/mus/test/ash_test_impl_mus.h"
 
 #include "ash/common/test/ash_test.h"
 #include "ash/common/wm_window.h"
 #include "base/memory/ptr_util.h"
 #include "services/ui/public/cpp/property_type_converters.h"
@@ skipping 28 matching lines @@
 AshTestImplMus::~AshTestImplMus() {}
 
 void AshTestImplMus::SetUp() {
   wm_test_base_->SetUp();
 }
 
 void AshTestImplMus::TearDown() {
   wm_test_base_->TearDown();
 }
 
-bool AshTestImplMus::SupportsMultipleDisplays() const {
-  return wm_test_base_->SupportsMultipleDisplays();
-}
-
 void AshTestImplMus::UpdateDisplay(const std::string& display_spec) {
   wm_test_base_->UpdateDisplay(display_spec);
 }
 
 std::unique_ptr<WindowOwner> AshTestImplMus::CreateTestWindow(
     const gfx::Rect& bounds_in_screen,
     ui::wm::WindowType type,
     int shell_window_id) {
   WmWindow* window =
       WmWindow::Get(wm_test_base_->CreateTestWindow(bounds_in_screen, type));
@@ skipping 38 matching lines @@
 }
 
 }  // namespace mus
 
 // static
 std::unique_ptr<AshTestImpl> AshTestImpl::Create() {
   return base::MakeUnique<mus::AshTestImplMus>();
 }
 
 }  // namespace ash