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

ui/gfx/screen_impl.h

-// 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.
-
-#ifndef UI_GFX_SCREEN_IMPL_H_
-#define UI_GFX_SCREEN_IMPL_H_
-
-#include "ui/gfx/display.h"
-#include "ui/gfx/native_widget_types.h"
-
-namespace gfx {
-class Display;
-class Point;
-class Rect;
-
-// A class that provides |gfx::Screen|'s implementation on aura.
-class UI_EXPORT ScreenImpl {
- public:
-  virtual ~ScreenImpl() {}
-
-  virtual gfx::Point GetCursorScreenPoint() = 0;
-  virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() = 0;
-
-  virtual int GetNumDisplays() = 0;
-  virtual gfx::Display GetDisplayNearestWindow(
-      gfx::NativeView window) const = 0;
-  virtual gfx::Display GetDisplayNearestPoint(
-      const gfx::Point& point) const = 0;
-  virtual gfx::Display GetDisplayMatching(
-      const gfx::Rect& match_rect) const = 0;
-  virtual gfx::Display GetPrimaryDisplay() const = 0;
-};
-
-}  // namespace gfx
-
-#endif  // UI_GFX_SCREEN_IMPL_H_