Add GetDisplayWithDisplayId to display::Screen.

ash/test/ash_test_base.cc

 // Copyright (c) 2012 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/test/ash_test_base.h"
 
 #include <string>
 #include <vector>
 
 #include "ash/common/test/test_session_state_delegate.h"
@@ skipping 199 matching lines @@
 bool AshTestBase::SupportsMultipleDisplays() {
   return AshTestHelper::SupportsMultipleDisplays();
 }
 
 // static
 void AshTestBase::UpdateDisplay(const std::string& display_specs) {
   display::test::DisplayManagerTestApi(Shell::GetInstance()->display_manager())
       .UpdateDisplay(display_specs);
 }
 
+int64_t AshTestBase::SetFirstDisplayAsInternalDisplay() {
+  return display::test::DisplayManagerTestApi(
+             Shell::GetInstance()->display_manager())
+      .SetFirstDisplayAsInternalDisplay();
+}
+
 aura::Window* AshTestBase::CurrentContext() {
   return ash_test_helper_->CurrentContext();
 }
 
 // static
 std::unique_ptr<views::Widget> AshTestBase::CreateTestWidget(
     views::WidgetDelegate* delegate,
     int container_id,
     const gfx::Rect& bounds) {
   std::unique_ptr<views::Widget> widget(new views::Widget);
@@ skipping 167 matching lines @@
 
 void AshTestBase::SwapPrimaryDisplay() {
   if (display::Screen::GetScreen()->GetNumDisplays() <= 1)
     return;
   Shell::GetInstance()->window_tree_host_manager()->SetPrimaryDisplayId(
       display_manager()->GetSecondaryDisplay().id());
 }
 
 }  // namespace test
 }  // namespace ash