Adds imageWriterPrivate support for Windows

chrome/chrome_tests.gypi

 # 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' : {
     'chromedriver_unittest_sources': [
       'test/chromedriver/capabilities_unittest.cc',
       'test/chromedriver/chrome/chrome_finder_unittest.cc',
       'test/chromedriver/chrome/console_logger_unittest.cc',
       'test/chromedriver/chrome/device_manager_unittest.cc',
@@ skipping 1263 matching lines @@
         'browser/external_extension_browsertest.cc',
         'browser/fast_shutdown_browsertest.cc',
         'browser/first_run/first_run_browsertest.cc',
         'browser/first_run/try_chrome_dialog_view_browsertest.cc',
         'browser/geolocation/access_token_store_browsertest.cc',
         'browser/geolocation/geolocation_browsertest.cc',
         'browser/history/history_browsertest.cc',
         'browser/history/multipart_browsertest.cc',
         'browser/history/redirect_browsertest.cc',
         'browser/iframe_browsertest.cc',
+        'browser/image_writer/image_writer_browsertest.cc',
+        'browser/image_writer/image_writer_test_utils.cc',
         'browser/importer/firefox_importer_browsertest.cc',
         'browser/importer/ie_importer_browsertest_win.cc',
         'browser/importer/importer_unittest_utils.cc',
         'browser/importer/importer_unittest_utils.h',
         'browser/infobars/infobar_extension_apitest.cc',
         'browser/infobars/infobars_browsertest.cc',
         'browser/lifetime/browser_close_manager_browsertest.cc',
         'browser/loadtimes_extension_bindings_browsertest.cc',
         'browser/locale_tests_browsertest.cc',
         'browser/logging_chrome_browsertest.cc',
@@ skipping 1946 matching lines @@
             'utility',
           ],
           'sources': [
             'tools/service_discovery_sniffer/service_discovery_sniffer.h',
             'tools/service_discovery_sniffer/service_discovery_sniffer.cc',
           ],
         }]
     }],
   ],  # 'conditions'
 }