Refactor screen/monitor so that gfx::Screen returns monitor object.

ui/views/widget/native_widget_aura_unittest.cc

Index: ui/views/widget/native_widget_aura_unittest.cc
diff --git a/ui/views/widget/native_widget_aura_unittest.cc b/ui/views/widget/native_widget_aura_unittest.cc
index 163f43c5c5c6a9846085eb52775552a36e50caef..5b74a12b984bee9c67aaba5d3e0a646d1c3d3e0f 100644
--- a/ui/views/widget/native_widget_aura_unittest.cc
+++ b/ui/views/widget/native_widget_aura_unittest.cc
@@ -18,8 +18,9 @@
 #include "ui/views/widget/root_view.h"
 #include "ui/views/widget/widget_delegate.h"
 
-#if defined(USE_ASH)
+#if defined(USE_AURA)
 #include "ui/aura/test/test_screen.h"
+#include "ui/gfx/screen.h"
 #endif
 
 namespace views {
@@ -44,7 +45,7 @@ class NativeWidgetAuraTest : public testing::Test {
         new aura::test::SingleMonitorManager);
     root_window_.reset(
         aura::MonitorManager::CreateRootWindowForPrimaryMonitor());
-#if defined(USE_ASH)
+#if defined(USE_AURA)
     gfx::Screen::SetInstance(new aura::TestScreen(root_window_.get()));
 #endif
     root_window_->SetBounds(gfx::Rect(0, 0, 640, 480));