Add workspace to desktop

ui/aura/toplevel_window_event_filter.h

Index: ui/aura/toplevel_window_event_filter.h
diff --git a/ui/aura/toplevel_window_event_filter.h b/ui/aura/toplevel_window_event_filter.h
index fcb9e67f87c0bb769cf31ec7f55399eb369d1260..5489f3b8eab054bff137fb5af43892a7c5d8b45e 100644
--- a/ui/aura/toplevel_window_event_filter.h
+++ b/ui/aura/toplevel_window_event_filter.h
@@ -26,6 +26,11 @@ class ToplevelWindowEventFilter : public EventFilter {
   virtual ui::TouchStatus OnTouchEvent(Window* target,
                                        TouchEvent* event) OVERRIDE;
 
+ protected:
+  // Returns the |window_component_|. See the variable definition below for
+  // more details.
+  int window_component() const { return window_component_; }
+
  private:
   // Moves the target window and all of its parents to the front of their
   // respective z-orders.