ui: Cleanup class/struct forward declarations

ui/views/test/widget_test.h

 // Copyright 2013 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_VIEWS_TEST_WIDGET_TEST_H_
 #define UI_VIEWS_TEST_WIDGET_TEST_H_
 
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "build/build_config.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/test/views_test_base.h"
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/views/widget/widget_observer.h"
 
 namespace ui {
 namespace internal {
 class InputMethodDelegate;
 }
 class EventProcessor;
 }
 
 namespace views {
 
-class NativeWidget;
 class Widget;
 
 namespace internal {
 
 class RootView;
 
 }  // namespace internal
 
 namespace test {
 
@@ skipping 136 matching lines @@
   bool observed_;
   bool active_;
 
   DISALLOW_COPY_AND_ASSIGN(WidgetActivationWaiter);
 };
 
 }  // namespace test
 }  // namespace views
 
 #endif  // UI_VIEWS_TEST_WIDGET_TEST_H_