Add context to gfx::Screen calls in support of simultaneous desktop+ash

ash/display/screen_position_controller_unittest.cc

Index: ash/display/screen_position_controller_unittest.cc
diff --git a/ash/display/screen_position_controller_unittest.cc b/ash/display/screen_position_controller_unittest.cc
index ed5e3ca8c4ab100ec0f69b4cdcf3b012d289f365..16e154d69feb83221ac514eff63a5133b79e1596 100644
--- a/ash/display/screen_position_controller_unittest.cc
+++ b/ash/display/screen_position_controller_unittest.cc
@@ -89,8 +89,9 @@ TEST_F(ScreenPositionControllerTest, MAYBE_ConvertNativePointToScreen) {
   EXPECT_EQ("200x200", root_windows[1]->GetHostSize().ToString());
 
   const gfx::Point window_pos(100, 100);
-  window_->SetBoundsInScreen(gfx::Rect(window_pos, gfx::Size(100, 100)),
-                             gfx::Screen::GetDisplayNearestPoint(window_pos));
+  window_->SetBoundsInScreen(
+      gfx::Rect(window_pos, gfx::Size(100, 100)),
+      ash::Shell::GetAshScreen()->GetDisplayNearestPoint(window_pos));
   SetSecondaryDisplayLayout(DisplayLayout::RIGHT);
   // The point is on the primary root window.
   EXPECT_EQ("150,150", ConvertNativePointToScreen(50, 50));
@@ -126,8 +127,9 @@ TEST_F(ScreenPositionControllerTest, MAYBE_ConvertNativePointToScreen) {
 
   SetSecondaryDisplayLayout(DisplayLayout::RIGHT);
   const gfx::Point window_pos2(300, 100);
-  window_->SetBoundsInScreen(gfx::Rect(window_pos2, gfx::Size(100, 100)),
-                             gfx::Screen::GetDisplayNearestPoint(window_pos2));
+  window_->SetBoundsInScreen(
+      gfx::Rect(window_pos2, gfx::Size(100, 100)),
+      ash::Shell::GetAshScreen()->GetDisplayNearestPoint(window_pos2));
   // The point is on the secondary display.
   EXPECT_EQ("350,150", ConvertNativePointToScreen(50, 50));
   // The point is out of the all root windows.