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

ash/wm/shelf_layout_manager.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/wm/shelf_layout_manager.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "ash/ash_switches.h"
@@ skipping 861 matching lines @@
     // Increase the the hit test area to prevent the shelf from disappearing
     // when the mouse is over the bubble gap.
     shelf_region.Inset(alignment_ == SHELF_ALIGNMENT_RIGHT ?
                            -kNotificationBubbleGapHeight : 0,
                        alignment_ == SHELF_ALIGNMENT_BOTTOM ?
                            -kNotificationBubbleGapHeight : 0,
                        alignment_ == SHELF_ALIGNMENT_LEFT ?
                            -kNotificationBubbleGapHeight : 0,
                        0);
   }
-  return shelf_region.Contains(gfx::Screen::GetCursorScreenPoint()) ?
+  return shelf_region.Contains(Shell::GetScreen()->GetCursorScreenPoint()) ?
       AUTO_HIDE_SHOWN : AUTO_HIDE_HIDDEN;
 }
 
 void ShelfLayoutManager::UpdateHitTestBounds() {
   gfx::Insets insets;
   // Only modify the hit test when the shelf is visible, so we don't mess with
   // hover hit testing in the auto-hide state.
   if (state_.visibility_state == VISIBLE) {
     // Let clicks at the very top of the launcher through so windows can be
     // resized with the bottom-right corner and bottom edge.
@@ skipping 27 matching lines @@
 int ShelfLayoutManager::GetWorkAreaSize(const State& state, int size) const {
   if (state.visibility_state == VISIBLE)
     return size;
   if (state.visibility_state == AUTO_HIDE)
     return kAutoHideSize;
   return 0;
 }
 
 }  // namespace internal
 }  // namespace ash