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

ash/screen_ash.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 ASH_SCREEN_ASH_H_
 #define ASH_SCREEN_ASH_H_
 
 #include "ash/ash_export.h"
 #include "base/compiler_specific.h"
-#include "ui/gfx/screen_impl.h"
+#include "ui/gfx/screen.h"
 
 namespace gfx {
 class Rect;
 }
 
 namespace ash {
 
 // Aura implementation of gfx::Screen. Implemented here to avoid circular
 // dependencies.
-class ASH_EXPORT ScreenAsh : public gfx::ScreenImpl {
+class ASH_EXPORT ScreenAsh : public gfx::Screen {
  public:
   ScreenAsh();
   virtual ~ScreenAsh();
 
   // Finds the display that contains |point| in screeen coordinates.
   // Returns invalid display if there is no display that can satisfy
   // the condition.
   static gfx::Display FindDisplayContainingPoint(const gfx::Point& point);
 
   // Returns the bounds for maximized windows in parent coordinates.
@@ skipping 18 matching lines @@
   // Converts |rect| from virtual screen coordinates to the |window|'s
   // coordinates.
   static gfx::Rect ConvertRectFromScreen(aura::Window* window,
                                          const gfx::Rect& rect);
 
   // Returns a gfx::Display object for secondary display. Returns
   // ivalid display if there is no secondary display connected.
   static const gfx::Display& GetSecondaryDisplay();
 
  protected:
+
+  // Implementation of gfx::Screen:
+  virtual bool IsDIPEnabled() OVERRIDE;
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
 
   virtual int GetNumDisplays() OVERRIDE;
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView view) const OVERRIDE;
   virtual gfx::Display GetDisplayNearestPoint(
       const gfx::Point& point) const OVERRIDE;
   virtual gfx::Display GetDisplayMatching(
       const gfx::Rect& match_rect) const OVERRIDE;
   virtual gfx::Display GetPrimaryDisplay() const OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScreenAsh);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SCREEN_ASH_H_