ui: Cleanup class/struct forward declarations

ui/views/view_targeter.h

 // Copyright 2014 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_VIEW_TARGETER_H_
 #define UI_VIEWS_VIEW_TARGETER_H_
 
 #include "base/macros.h"
 #include "ui/events/event_targeter.h"
 #include "ui/views/views_export.h"
 
 namespace gfx {
 class Rect;
 }  // namespace gfx
 
 namespace ui {
 class GestureEvent;
 class KeyEvent;
 class ScrollEvent;
 }  // namespace ui
 
 namespace views {
 
-namespace internal {
-class RootView;
-}  // namespace internal
-
 class View;
 class ViewTargeterDelegate;
 
 // A ViewTargeter is installed on a View that wishes to use the custom
 // hit-testing or event-targeting behaviour defined by |delegate|.
 class VIEWS_EXPORT ViewTargeter : public ui::EventTargeter {
  public:
   explicit ViewTargeter(ViewTargeterDelegate* delegate);
   ~ViewTargeter() override;
 
@@ skipping 23 matching lines @@
   // ViewTargeter does not own the |delegate_|, but |delegate_| must
   // outlive the targeter.
   ViewTargeterDelegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewTargeter);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_TARGETER_H_