ui: Cleanup class/struct forward declarations

ui/views/widget/desktop_aura/desktop_native_widget_aura.h

 // Copyright (c) 2012 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_WIDGET_DESKTOP_AURA_DESKTOP_NATIVE_WIDGET_AURA_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_NATIVE_WIDGET_AURA_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "ui/aura/client/drag_drop_delegate.h"
 #include "ui/aura/client/focus_change_observer.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_tree_host_observer.h"
 #include "ui/base/cursor/cursor.h"
 #include "ui/views/widget/native_widget_private.h"
 #include "ui/wm/core/compound_event_filter.h"
 #include "ui/wm/public/activation_change_observer.h"
 #include "ui/wm/public/activation_delegate.h"
 
 namespace aura {
 class WindowEventDispatcher;
 class WindowTreeHost;
 namespace client {
 class DragDropClient;
-class FocusClient;
 class ScreenPositionClient;
 class WindowParentingClient;
 }
 }
 
 namespace wm {
 class CompoundEventFilter;
 class CursorManager;
 class FocusController;
 class ShadowController;
@@ skipping 272 matching lines @@
   // The following factory is used for calls to close the NativeWidgetAura
   // instance.
   base::WeakPtrFactory<DesktopNativeWidgetAura> close_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopNativeWidgetAura);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_NATIVE_WIDGET_AURA_H_