Move FileEnumerator to its own file, do some refactoring.

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 142 matching lines @@
           'file_util_posix.cc',
           'file_util_win.cc',
           'file_version_info.h',
           'file_version_info_mac.h',
           'file_version_info_mac.mm',
           'file_version_info_win.cc',
           'file_version_info_win.h',
           'files/dir_reader_fallback.h',
           'files/dir_reader_linux.h',
           'files/dir_reader_posix.h',
+          'files/file_enumerator.cc',
+          'files/file_enumerator.h',
+          'files/file_enumerator_posix.cc',
+          'files/file_enumerator_win.cc',
           'files/file_path.cc',
           'files/file_path.h',
           'files/file_path_constants.cc',
           'files/file_path_watcher.cc',
           'files/file_path_watcher.h',
           'files/file_path_watcher_kqueue.cc',
           'files/file_path_watcher_linux.cc',
           'files/file_path_watcher_stub.cc',
           'files/file_path_watcher_win.cc',
           'files/file_util_proxy.cc',
@@ skipping 483 matching lines @@
           ['>(nacl_untrusted_build)==1', {
             'sources!': [
                'allocator/type_profiler_control.cc',
                'allocator/type_profiler_control.h',
                'base_paths.cc',
                'cpu.cc',
                'debug/stack_trace_posix.cc',
                'file_util.cc',
                'file_util_posix.cc',
                'file_util_proxy.cc',
+               'files/file_enumerator_posix.cc',
                'files/file_path_watcher_kqueue.cc',
                'memory/shared_memory_posix.cc',
                'native_library_posix.cc',
                'path_service.cc',
                'platform_file_posix.cc',
                'posix/unix_domain_socket_linux.cc',
                'process_posix.cc',
                'process_util.cc',
                'process_util_posix.cc',
                'rand_util_posix.cc',
@@ skipping 155 matching lines @@
           ['<(use_system_nspr)==1 and >(nacl_untrusted_build)==0', {
             'sources/': [
               ['exclude', '^third_party/nspr/'],
             ],
           }],
         ],
       }],
     ],
   },
 }