Move storage-related files from webkit/ to new top-level directory storage/

webkit/common/webkit_common.gyp

-# Copyright 2013 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': {
-    'enable_wexit_time_destructors': 1,
-    'chromium_code': 1
-  },
-  'targets': [
-    {
-      # GN version: //webkit/common:common",
-      'target_name': 'webkit_common',
-      'type': '<(component)',
-      'defines': [
-        'WEBKIT_COMMON_IMPLEMENTATION',
-      ],
-      'dependencies': [
-        '../../base/base.gyp:base',
-        '../../url/url.gyp:url_lib',
-      ],
-      'sources': [
-        'data_element.cc',
-        'data_element.h',
-        'webkit_common_export.h',
-      ],
-    },
-  ],
-}