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

ui/aura/desktop/desktop_screen_win.h

Index: ui/aura/desktop/desktop_screen_win.h
diff --git a/ui/aura/desktop/desktop_screen_win.h b/ui/aura/desktop/desktop_screen_win.h
index 7d67b195e673921e0fa423b3018cebbfdfe08d7b..2ec08a9deeca7a1dc19d3f12f52eb8492753f0ae 100644
--- a/ui/aura/desktop/desktop_screen_win.h
+++ b/ui/aura/desktop/desktop_screen_win.h
@@ -6,16 +6,17 @@
 #define UI_AURA_DESKTOP_DESKTOP_SCREEN_WIN_H_
 
 #include "ui/aura/aura_export.h"
-#include "ui/gfx/screen_impl.h"
+#include "ui/gfx/screen.h"
 
 namespace aura {
 
-class AURA_EXPORT DesktopScreenWin : public gfx::ScreenImpl {
+class AURA_EXPORT DesktopScreenWin : public gfx::Screen {
 public:
   DesktopScreenWin();
   virtual ~DesktopScreenWin();
 
-  // Overridden from gfx::ScreenImpl:
+  // Overridden from gfx::Screen:
+  virtual bool IsDIPEnabled() OVERRIDE;
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
   virtual int GetNumDisplays() OVERRIDE;