Move FileDescriptorShuffle to base/posix. This file is very posix-specific.

base/base.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.
 
 {
   'target_defaults': {
     'variables': {
       'base_target': 0,
     },
     'target_conditions': [
@@ skipping 652 matching lines @@
           ['OS != "android" or >(nacl_untrusted_build)==1', {
               'sources/': [ ['exclude', '^android/'] ],
             },
           ],
           ['OS == "win" and >(nacl_untrusted_build)==0', {
             'include_dirs': [
               '<(DEPTH)/third_party/wtl/include',
             ],
             'sources!': [
               'event_recorder_stubs.cc',
-              'file_descriptor_shuffle.cc',
               'files/file_path_watcher_kqueue.cc',
               'files/file_path_watcher_stub.cc',
               'message_pump_libevent.cc',
+              'posix/file_descriptor_shuffle.cc',
               # Not using sha1_win.cc because it may have caused a
               # regression to page cycler moz.
               'sha1_win.cc',
               'string16.cc',
             ],
           },],
           ['OS == "linux" and >(nacl_untrusted_build)==0', {
             'sources!': [
               'files/file_path_watcher_kqueue.cc',
               'files/file_path_watcher_stub.cc',
@@ skipping 25 matching lines @@
           # Remove all unnecessary files for build_nexe.py to avoid exceeding
           # command-line-string limitation when building NaCl on Windows.
           ['OS == "win" and >(nacl_untrusted_build)==1', {
               'sources/': [ ['exclude', '\\.h$'] ],
           }],
         ],
       }],
     ],
   },
 }