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

ui/aura/desktop/desktop_screen_win.cc

Index: ui/aura/desktop/desktop_screen_win.cc
diff --git a/ui/aura/desktop/desktop_screen_win.cc b/ui/aura/desktop/desktop_screen_win.cc
index 593f4f2d8f58cc6f8935dffba74649d2e02dc5e7..d44b567044864afe8f28e1f1b45e459800e0a740 100644
--- a/ui/aura/desktop/desktop_screen_win.cc
+++ b/ui/aura/desktop/desktop_screen_win.cc
@@ -40,7 +40,11 @@ DesktopScreenWin::~DesktopScreenWin() {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// DesktopScreenWin, gfx::ScreenImpl implementation:
+// DesktopScreenWin, gfx::Screen implementation:
+
+bool DesktopScreenWin::IsDIPEnabled() {
+  return true;
+}
 
 gfx::Point DesktopScreenWin::GetCursorScreenPoint() {
   POINT pt;
@@ -101,7 +105,7 @@ gfx::Display DesktopScreenWin::GetPrimaryDisplay() const {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-gfx::ScreenImpl* CreateDesktopScreen() {
+gfx::Screen* CreateDesktopScreen() {
   return new DesktopScreenWin;
 }