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

ash/wm/shelf_layout_manager_unittest.cc

Index: ash/wm/shelf_layout_manager_unittest.cc
diff --git a/ash/wm/shelf_layout_manager_unittest.cc b/ash/wm/shelf_layout_manager_unittest.cc
index 559316e75fee77d0eb136980c328961936e31fb0..b9beced39829e06fc57551213e778efaa969094b 100644
--- a/ash/wm/shelf_layout_manager_unittest.cc
+++ b/ash/wm/shelf_layout_manager_unittest.cc
@@ -13,7 +13,7 @@
 #include "ash/test/ash_test_base.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
-#include "ui/aura/monitor.h"
+#include "ui/aura/monitor_aura.h"
 #include "ui/aura/monitor_manager.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/test/event_generator.h"
@@ -86,7 +86,7 @@ TEST_F(ShelfLayoutManagerTest, MAYBE_SetVisible) {
   EXPECT_EQ(ShelfLayoutManager::VISIBLE, shelf->visibility_state());
   const aura::MonitorManager* manager =
       aura::Env::GetInstance()->monitor_manager();
-  const aura::Monitor* monitor =
+  const aura::MonitorAura* monitor =
       manager->GetMonitorNearestWindow(Shell::GetRootWindow());
   ASSERT_TRUE(monitor);
   // Bottom inset should be the max of widget heights.
@@ -137,7 +137,7 @@ TEST_F(ShelfLayoutManagerTest, LayoutShelfWhileAnimating) {
 
   const aura::MonitorManager* manager =
       aura::Env::GetInstance()->monitor_manager();
-  const aura::Monitor* monitor =
+  const aura::MonitorAura* monitor =
       manager->GetMonitorNearestWindow(Shell::GetRootWindow());
 
   // Hide the shelf.