Remove now-unnecessary wrappers around gfx::Screen::GetScreen()

ash/system/web_notification/web_notification_tray_unittest.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/system/web_notification/web_notification_tray.h"
 
 #include <utility>
 #include <vector>
 
 #include "ash/display/display_manager.h"
@@ skipping 418 matching lines @@
 
   // The work area for auto-hidden status of fullscreen is a bit larger
   // since it doesn't even have the 3-pixel width.
   EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->auto_hide_state());
   int bottom_fullscreen_hidden = GetPopupWorkAreaBottom();
   EXPECT_EQ(bottom_auto_hidden, bottom_fullscreen_hidden);
 
   // Move the mouse cursor at the bottom, which shows the shelf.
   ui::test::EventGenerator generator(Shell::GetPrimaryRootWindow());
   gfx::Point bottom_right =
-      Shell::GetScreen()->GetPrimaryDisplay().bounds().bottom_right();
+      gfx::Screen::GetScreen()->GetPrimaryDisplay().bounds().bottom_right();
   bottom_right.Offset(-1, -1);
   generator.MoveMouseTo(bottom_right);
   shelf->UpdateAutoHideStateNow();
   EXPECT_EQ(SHELF_AUTO_HIDE_SHOWN, shelf->auto_hide_state());
   EXPECT_EQ(bottom, GetPopupWorkAreaBottom());
 
   generator.MoveMouseTo(
-      Shell::GetScreen()->GetPrimaryDisplay().bounds().CenterPoint());
+      gfx::Screen::GetScreen()->GetPrimaryDisplay().bounds().CenterPoint());
   shelf->UpdateAutoHideStateNow();
   EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->auto_hide_state());
   EXPECT_EQ(bottom_auto_hidden, GetPopupWorkAreaBottom());
 }
 
 TEST_F(WebNotificationTrayTest, MAYBE_PopupAndSystemTrayMultiDisplay) {
   UpdateDisplay("800x600,600x400");
 
   AddNotification("test_id");
   int bottom = GetPopupWorkAreaBottom();
@@ skipping 64 matching lines @@
   ui::TouchEvent release(ui::ET_TOUCH_RELEASED, out_of_bounds, touch_id,
       move.time_stamp()+base::TimeDelta::FromMilliseconds(50));
   generator.Dispatch(&release);
   EXPECT_FALSE(tray->draw_background_as_active());
   EXPECT_FALSE(tray->IsMessageCenterBubbleVisible());
 }
 
 #endif  // OS_CHROMEOS
 
 }  // namespace ash