Cleanup: Remove unneeded forward declarations in views.

views/controls/menu/native_menu_host.h

 // Copyright (c) 2011 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 VIEWS_CONTROLS_MENU_NATIVE_MENU_HOST_H_
 #define VIEWS_CONTROLS_MENU_NATIVE_MENU_HOST_H_
 
 #include "ui/gfx/native_widget_types.h"
 
-namespace gfx {
-class Rect;
-}
+namespace views {
 
-namespace views {
 class NativeWidget;
+
 namespace internal {
 class NativeMenuHostDelegate;
 }
 
 class NativeMenuHost {
  public:
   virtual ~NativeMenuHost() {}
 
   static NativeMenuHost* CreateNativeMenuHost(
       internal::NativeMenuHostDelegate* delegate);
 
   // Starts capturing input events.
   virtual void StartCapturing() = 0;
 
   virtual NativeWidget* AsNativeWidget() = 0;
 };
 
 }  // namespace views
 
 #endif  // VIEWS_CONTROLS_MENU_NATIVE_MENU_HOST_H_