Adds web::NavigationItem.

ios/web/ios_web.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
    },
   'targets': [
     {
       'target_name': 'ios_web',
       'type': 'static_library',
       'include_dirs': [
         '../..',
       ],
       'dependencies': [
         '../../base/base.gyp:base',
       ],
       'sources': [
+        'public/navigation_item.h',
         'public/user_agent.h',
         'public/user_agent.mm',
       ],
     },
   ],
 }