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

ash/display/cursor_window_controller_unittest.cc

 // Copyright 2015 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/display/cursor_window_controller.h"
 
 #include "ash/display/display_util.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
@@ skipping 136 matching lines @@
   // Cursor was shown.
   SetCursorCompositionEnabled(true);
   ASSERT_TRUE(GetCursorWindow());
   EXPECT_TRUE(GetCursorWindow()->IsVisible());
 }
 
 // Make sure that composition cursor stays big even when
 // the DSF becomes 1x as a result of zooming out.
 TEST_F(CursorWindowControllerTest, DSF) {
   UpdateDisplay("1000x500*2");
-  int64_t primary_id = Shell::GetScreen()->GetPrimaryDisplay().id();
+  int64_t primary_id = gfx::Screen::GetScreen()->GetPrimaryDisplay().id();
 
   test::ScopedSetInternalDisplayId set_internal(primary_id);
   SetCursorCompositionEnabled(true);
-  ASSERT_EQ(2.0f,
-            Shell::GetScreen()->GetPrimaryDisplay().device_scale_factor());
+  ASSERT_EQ(
+      2.0f,
+      gfx::Screen::GetScreen()->GetPrimaryDisplay().device_scale_factor());
   EXPECT_TRUE(GetCursorImage().HasRepresentation(2.0f));
 
   ASSERT_TRUE(SetDisplayUIScale(primary_id, 2.0f));
-  ASSERT_EQ(1.0f,
-            Shell::GetScreen()->GetPrimaryDisplay().device_scale_factor());
+  ASSERT_EQ(
+      1.0f,
+      gfx::Screen::GetScreen()->GetPrimaryDisplay().device_scale_factor());
   EXPECT_TRUE(GetCursorImage().HasRepresentation(2.0f));
 }
 #endif
 
 }  // namespace ash