Move DisplayUtils methods into gfx::Screen.

ui/aura/screen_aura.cc

 // Copyright (c) 2011 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 "ui/aura/screen_aura.h"
 
 #include "base/logging.h"
 #include "ui/aura/desktop.h"
 #include "ui/aura/window.h"
 #include "ui/gfx/native_widget_types.h"
@@ skipping 37 matching lines @@
 gfx::Rect ScreenAura::GetBounds() {
   return gfx::Rect(aura::Desktop::GetInstance()->GetHostSize());
 }
 
 gfx::Rect ScreenAura::GetWorkAreaBounds() {
   gfx::Rect bounds(GetBounds());
   bounds.Inset(work_area_insets_);
   return bounds;
 }
 
+gfx::Size ScreenAura::GetPrimaryMonitorSizeImpl() {
+  return GetMonitorWorkAreaNearestPoint(gfx::Point()).size();
+}
+
+int ScreenAura::GetNumMonitorsImpl() {
+  return 1;
+}
+
 }  // namespace aura