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

ash/wm/gestures/bezel_gesture_handler.cc

Index: ash/wm/gestures/bezel_gesture_handler.cc
diff --git a/ash/wm/gestures/bezel_gesture_handler.cc b/ash/wm/gestures/bezel_gesture_handler.cc
index eb43de8f6872e3433a9c47920032b232e292f1d1..f3610a6dd4b574e318cd50eca3bfdf619dcde090 100644
--- a/ash/wm/gestures/bezel_gesture_handler.cc
+++ b/ash/wm/gestures/bezel_gesture_handler.cc
@@ -160,7 +160,8 @@ bool BezelGestureHandler::HandleApplicationControl(
 void BezelGestureHandler::HandleBezelGestureStart(
     aura::Window* target,
     const ui::GestureEvent& event) {
-  gfx::Rect screen = gfx::Screen::GetDisplayNearestWindow(target).bounds();
+  gfx::Rect screen =
+      Shell::GetAshScreen()->GetDisplayNearestWindow(target).bounds();
   int overlap_area = screen.width() * overlap_percent_ / 100;
   orientation_ = SCROLL_ORIENTATION_UNSET;
 
@@ -214,7 +215,8 @@ void BezelGestureHandler::HandleBezelGestureUpdate(
         start_location_ = BEZEL_START_UNSET;
         return;
       }
-      gfx::Rect screen = gfx::Screen::GetDisplayNearestWindow(target).bounds();
+      gfx::Rect screen =
+          Shell::GetAshScreen()->GetDisplayNearestWindow(target).bounds();
       // Limit the user gesture "mostly" to the off screen area and check for
       // noise invocation.
       if (!GestureInBezelArea(screen, event) ||