Move enum MenuAnchorPosition to reduce deps on menu_item_view.h

ui/views/controls/menu/menu_message_pump_dispatcher_win.cc

 // 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.
 
 #include "ui/views/controls/menu/menu_message_pump_dispatcher_win.h"
 
 #include <windowsx.h>
 
 #include "ui/events/event_utils.h"
 #include "ui/events/keycodes/keyboard_code_conversion.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/views/controls/menu/menu_controller.h"
+#include "ui/views/controls/menu/menu_item_view.h"
 
 namespace views {
 namespace internal {
 
 MenuMessagePumpDispatcher::MenuMessagePumpDispatcher(MenuController* controller)
     : menu_controller_(controller) {}
 
 MenuMessagePumpDispatcher::~MenuMessagePumpDispatcher() {}
 
 uint32_t MenuMessagePumpDispatcher::Dispatch(const MSG& msg) {
@@ skipping 51 matching lines @@
       break;
   }
   return POST_DISPATCH_PERFORM_DEFAULT |
          (menu_controller_->exit_type() == MenuController::EXIT_NONE
               ? POST_DISPATCH_NONE
               : POST_DISPATCH_QUIT_LOOP);
 }
 
 }  // namespace internal
 }  // namespace views