components: Cleanup class/struct fwd declarations

components/exo/pointer.h

 // Copyright 2015 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 COMPONENTS_EXO_POINTER_H_
 #define COMPONENTS_EXO_POINTER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/exo/surface_delegate.h"
 #include "components/exo/surface_observer.h"
 #include "components/exo/wm_helper.h"
 #include "ui/events/event_handler.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_f.h"
 
 namespace ui {
 class Event;
 class MouseEvent;
-class MouseWheelEvent;
 }
 
 namespace views {
 class Widget;
 }
 
 namespace exo {
 class PointerDelegate;
 class PointerStylusDelegate;
 class Surface;
@@ skipping 77 matching lines @@
 
   // True if the pointer is controlled via direct input.
   bool is_direct_input_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(Pointer);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_POINTER_H_