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

ui/views/controls/menu/menu_controller.h

Index: ui/views/controls/menu/menu_controller.h
diff --git a/ui/views/controls/menu/menu_controller.h b/ui/views/controls/menu/menu_controller.h
index e29b1a147ae623b1a520bc9eef399dd20957b379..b22bc22e521746f34233cf7143e8daa2ea1a9873 100644
--- a/ui/views/controls/menu/menu_controller.h
+++ b/ui/views/controls/menu/menu_controller.h
@@ -31,6 +31,9 @@ class Window;
 namespace ui {
 class OSExchangeData;
 }
+namespace gfx {
+class Screen;
+}
 namespace views {
 
 class DropTargetEvent;
@@ -461,6 +464,9 @@ class VIEWS_EXPORT MenuController
                                  aura::Window* old_active) OVERRIDE;
 #endif
 
+  // Retrieve an appropriate Screen.
+  gfx::Screen* GetScreen();
+
   // The active instance.
   static MenuController* active_instance_;