Make webkit_storage build on Win64

webkit/storage/webkit_storage.gypi

 # 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': {
     'conditions': [
       ['inside_chromium_build==0', {
         'webkit_src_dir': '../../../../..',
       },{
@@ skipping 46 matching lines @@
           'sources': [
             '<@(webkit_fileapi_chromeos_sources)',
           ],
         }],
         ['OS=="linux" or chromeos==1 or OS=="win"', {
           'sources': [
             '<@(webkit_fileapi_media_sources)',
           ],
         }],
       ],
+      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+      'msvs_disabled_warnings': [ 4267, ],
     },
   ],
 }