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

ui/aura/test/aura_test_base.cc

Index: ui/aura/test/aura_test_base.cc
diff --git a/ui/aura/test/aura_test_base.cc b/ui/aura/test/aura_test_base.cc
index 9a0a7ae3689209d26cccdae6081132e80f75d6f1..97849816d4b147a441e10eae3e429f90dacbb171 100644
--- a/ui/aura/test/aura_test_base.cc
+++ b/ui/aura/test/aura_test_base.cc
@@ -8,15 +8,13 @@
 #include "ui/aura/monitor_manager.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/single_monitor_manager.h"
+#include "ui/aura/test/test_screen.h"
 #include "ui/aura/test/test_stacking_client.h"
 #include "ui/aura/ui_controls_aura.h"
 #include "ui/base/gestures/gesture_configuration.h"
+#include "ui/gfx/screen.h"
 #include "ui/ui_controls/ui_controls.h"
 
-#if defined(USE_ASH)
-#include "ui/aura/test/test_screen.h"
-#endif
-
 namespace aura {
 namespace test {
 
@@ -53,9 +51,7 @@ void AuraTestBase::SetUp() {
   Env::GetInstance()->SetMonitorManager(new SingleMonitorManager);
   root_window_.reset(Env::GetInstance()->monitor_manager()->
                      CreateRootWindowForPrimaryMonitor());
-#if defined(USE_ASH)
   gfx::Screen::SetInstance(new aura::TestScreen(root_window_.get()));
-#endif
   ui_controls::InstallUIControlsAura(CreateUIControlsAura(root_window_.get()));
   helper_.InitRootWindow(root_window());
   helper_.SetUp();