Move enum MenuAnchorPosition to reduce deps on menu_item_view.h

ui/views/views.gyp

 # 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.
 {
   'variables': {
     'chromium_code': 1,
   },
   'target_defaults': {
     'conditions': [
       ['use_aura==1', {
@@ skipping 136 matching lines @@
         'controls/menu/menu_model_adapter.cc',
         'controls/menu/menu_model_adapter.h',
         'controls/menu/menu_runner.cc',
         'controls/menu/menu_runner.h',
         'controls/menu/menu_runner_handler.h',
         'controls/menu/menu_scroll_view_container.cc',
         'controls/menu/menu_scroll_view_container.h',
         'controls/menu/menu_separator.h',
         'controls/menu/menu_separator_views.cc',
         'controls/menu/menu_separator_win.cc',
+        'controls/menu/menu_types.h',
         'controls/menu/menu_wrapper.h',
         'controls/menu/native_menu_win.cc',
         'controls/menu/native_menu_win.h',
         'controls/menu/menu_image_util.cc',
         'controls/menu/menu_image_util.h',
         'controls/menu/submenu_view.cc',
         'controls/menu/submenu_view.h',
         'controls/message_box_view.cc',
         'controls/message_box_view.h',
         'controls/native/native_view_host.cc',
@@ skipping 539 matching lines @@
         }],
         ['use_aura==1', {
           'dependencies': [
             '../aura/aura.gyp:aura_test_support',
           ],
         }],
       ],
     },  # target_name: views_unittests
   ],
 }