Fixes bugs in cursor handling

services/ui/ws/event_dispatcher.h

Index: services/ui/ws/event_dispatcher.h
diff --git a/services/ui/ws/event_dispatcher.h b/services/ui/ws/event_dispatcher.h
index cd05854cf1fb194406c426207cca052e0bfecfbb..79fe864e6e889198c1184849f5e8e38db7eebcdf 100644
--- a/services/ui/ws/event_dispatcher.h
+++ b/services/ui/ws/event_dispatcher.h
@@ -114,6 +114,11 @@ class EventDispatcher : public ServerWindowObserver, public DragCursorUpdater {
     return mouse_cursor_source_window_;
   }
 
+  // Returns the window the mouse cursor is taken from. This does not take
+  // into account drags. In other words if there is a drag on going the mouse
+  // comes comes from a different window.
+  const ServerWindow* GetWindowForMouseCursor() const;
+
   // If the mouse cursor is still over |mouse_cursor_source_window_|, updates
   // whether we are in the non-client area. Used when
   // |mouse_cursor_source_window_| has changed its properties.