wayland: define base:NativeEvent for Wayland

ui/wayland/wayland_widget.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_WAYLAND_WAYLAND_WIDGET_H_
 #define UI_WAYLAND_WAYLAND_WIDGET_H_
 
-#include "ui/wayland/events/wayland_event.h"
+namespace base {
+namespace wayland {
+union WaylandEvent;
+}
+}
 
 namespace ui {
 
 // WaylandWidget is an interface for processing Wayland events.
 class WaylandWidget {
  public:
   virtual ~WaylandWidget() {}
 
-  virtual void OnMotionNotify(WaylandEvent event) = 0;
-  virtual void OnButtonNotify(WaylandEvent event) = 0;
-  virtual void OnKeyNotify(WaylandEvent event) = 0;
-  virtual void OnPointerFocus(WaylandEvent event) = 0;
-  virtual void OnKeyboardFocus(WaylandEvent event) = 0;
+  virtual void OnMotionNotify(base::wayland::WaylandEvent event) = 0;
+  virtual void OnButtonNotify(base::wayland::WaylandEvent event) = 0;
+  virtual void OnKeyNotify(base::wayland::WaylandEvent event) = 0;
+  virtual void OnPointerFocus(base::wayland::WaylandEvent event) = 0;
+  virtual void OnKeyboardFocus(base::wayland::WaylandEvent event) = 0;
 
-  virtual void OnGeometryChange(WaylandEvent event) = 0;
+  virtual void OnGeometryChange(base::wayland::WaylandEvent event) = 0;
 };
 
 }  // namespace ui
 
 #endif  // UI_WAYLAND_WAYLAND_WIDGET_H_