Ensure that in Desktop AURA the WindowModalityController class is at the head of the event pre targ…

ui/events/event_target.h

Index: ui/events/event_target.h
===================================================================
--- ui/events/event_target.h	(revision 226033)
+++ ui/events/event_target.h	(working copy)
@@ -70,6 +70,9 @@
   void AddPostTargetHandler(EventHandler* handler);
   void RemovePostTargetHandler(EventHandler* handler);
 
+  // Returns true if the event pre target list is empty.
+  bool IsPreTargetListEmpty() const;
+
  protected:
   void set_target_handler(EventHandler* handler) {
     target_handler_ = handler;