ui: Cleanup class/struct forward declarations

ui/views/focus/focus_manager.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_FOCUS_FOCUS_MANAGER_H_
 #define UI_VIEWS_FOCUS_FOCUS_MANAGER_H_
 
 #include <list>
 #include <map>
 #include <memory>
@@ skipping 59 matching lines @@
 //
 //     hwnd_view_container_->GetWidget()->SetFocusTraversableParent(
 //         native_control);
 //
 // Note that FocusTraversable views do not have to be RootViews:
 // AccessibleToolbarView is FocusTraversable.
 
 namespace ui {
 class AcceleratorManager;
 class AcceleratorTarget;
-class EventHandler;
 class KeyEvent;
 }
 
 namespace views {
 
 class FocusManagerDelegate;
 class FocusSearch;
 class View;
 class Widget;
 
@@ skipping 292 matching lines @@
   // access is enabled.
   // Default value is false.
   bool keyboard_accessible_;
 
   DISALLOW_COPY_AND_ASSIGN(FocusManager);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_FOCUS_FOCUS_MANAGER_H_