Add context to gfx::Screen calls in support of simultaneous desktop+ash

ui/aura/test/aura_test_helper.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 "ui/aura/test/aura_test_helper.h"
 
 #include "base/message_loop.h"
 #include "base/run_loop.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
@@ skipping 28 matching lines @@
   CHECK(setup_called_)
       << "You have overridden SetUp but never called super class's SetUp";
   CHECK(teardown_called_)
       << "You have overridden TearDown but never called super class's TearDown";
 }
 
 void AuraTestHelper::SetUp() {
   setup_called_ = true;
   Env::GetInstance()->SetDisplayManager(new SingleDisplayManager);
   root_window_.reset(aura::DisplayManager::CreateRootWindowForPrimaryDisplay());
-  gfx::Screen::SetInstance(new aura::TestScreen(root_window_.get()));
+  gfx::Screen::SetScreenInstance(
+      gfx::SCREEN_TYPE_NATIVE, new aura::TestScreen(root_window_.get()));
   ui_controls::InstallUIControlsAura(CreateUIControlsAura(root_window_.get()));
 
   focus_manager_.reset(new FocusManager);
   root_window_->set_focus_manager(focus_manager_.get());
   stacking_client_.reset(new TestStackingClient(root_window_.get()));
   test_activation_client_.reset(
       new test::TestActivationClient(root_window_.get()));
   root_window_capture_client_.reset(
       new shared::RootWindowCaptureClient(root_window_.get()));
   test_input_method_.reset(new ui::test::DummyInputMethod);
@@ skipping 21 matching lines @@
 #if !defined(OS_MACOSX)
   // TODO(jbates) crbug.com/134753 Find quitters of this RunLoop and have them
   //              use run_loop.QuitClosure().
   base::RunLoop run_loop(Env::GetInstance()->GetDispatcher());
   run_loop.RunUntilIdle();
 #endif
 }
 
 }  // namespace test
 }  // namespace aura