events: Move EventTarget into Event.

ui/base/events/event_handler.h

Index: ui/base/events/event_handler.h
diff --git a/ui/base/events/event_handler.h b/ui/base/events/event_handler.h
index e331bdc83e424159c0d22de144ddc08476820fa6..4d881dd1e7d55f7396a36d0df2ea73dcf0c011bc 100644
--- a/ui/base/events/event_handler.h
+++ b/ui/base/events/event_handler.h
@@ -26,20 +26,15 @@ class UI_EXPORT EventHandler {
   EventHandler() {}
   virtual ~EventHandler() {}
 
-  virtual EventResult OnKeyEvent(EventTarget* target,
-                                 KeyEvent* event) = 0;
+  virtual EventResult OnKeyEvent(KeyEvent* event) = 0;
 
-  virtual EventResult OnMouseEvent(EventTarget* target,
-                                   MouseEvent* event) = 0;
+  virtual EventResult OnMouseEvent(MouseEvent* event) = 0;
 
-  virtual EventResult OnScrollEvent(EventTarget* target,
-                                    ScrollEvent* event) = 0;
+  virtual EventResult OnScrollEvent(ScrollEvent* event) = 0;
 
-  virtual TouchStatus OnTouchEvent(EventTarget* target,
-                                   TouchEvent* event) = 0;
+  virtual TouchStatus OnTouchEvent(TouchEvent* event) = 0;
 
-  virtual EventResult OnGestureEvent(EventTarget* target,
-                                     GestureEvent* event) = 0;
+  virtual EventResult OnGestureEvent(GestureEvent* event) = 0;
 };
 
 typedef std::vector<EventHandler*> EventHandlerList;