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

ash/wm/window_animations.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/window_animations.h"
 
 #include <math.h>
 
 #include <algorithm>
 #include <vector>
@@ skipping 380 matching lines @@
       ui::LayerAnimator::IMMEDIATELY_SET_NEW_TARGET);
 }
 
 gfx::Rect GetMinimizeRectForWindow(aura::Window* window) {
   gfx::Rect target_bounds = Shell::GetInstance()->launcher()->
       GetScreenBoundsOfItemIconForWindow(window);
   if (target_bounds.IsEmpty()) {
     // Assume the launcher is overflowed, zoom off to the bottom right of the
     // work area.
     gfx::Rect work_area =
-        gfx::Screen::GetDisplayNearestWindow(window).work_area();
+        Shell::GetScreen()->GetDisplayNearestWindow(window).work_area();
     target_bounds.SetRect(work_area.right(), work_area.bottom(), 0, 0);
   }
   target_bounds =
       ScreenAsh::ConvertRectFromScreen(window->parent(), target_bounds);
   return target_bounds;
 }
 
 void AddLayerAnimationsForMinimize(aura::Window* window, bool show) {
   // Recalculate the transform at restore time since the launcher item may have
   // moved while the window was minimized.
@@ skipping 752 matching lines @@
     return AnimateShowWindow(window);
   } else {
     // Don't start hiding the window again if it's already being hidden.
     return window->layer()->GetTargetOpacity() != 0.0f &&
         AnimateHideWindow(window);
   }
 }
 
 }  // namespace internal
 }  // namespace ash