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

ash/system/tray/system_tray.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/tray/system_tray.h"
 
 #include "ash/shell.h"
 #include "ash/shell/panel_window.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/audio/tray_volume.h"
@@ skipping 230 matching lines @@
     return true;
   if (notification_bubble_.get() && notification_bubble_->IsVisible())
     return true;
   return false;
 }
 
 bool SystemTray::IsMouseInNotificationBubble() const {
   if (!notification_bubble_.get())
     return false;
   return notification_bubble_->bubble_view()->GetBoundsInScreen().Contains(
-      gfx::Screen::GetCursorScreenPoint());
+      Shell::GetScreen()->GetCursorScreenPoint());
 }
 
 bool SystemTray::CloseBubbleForTest() const {
   if (!bubble_.get())
     return false;
   bubble_->Close();
   return true;
 }
 
 // Private methods.
@@ skipping 204 matching lines @@
         ConvertPointToWidget(this, &point);
         arrow_offset = point.x();
       }
     }
     ShowDefaultViewWithOffset(BUBBLE_CREATE_NEW, arrow_offset);
   }
   return true;
 }
 
 }  // namespace ash