Get gn_all/gyp_remaining working for Windows.

build/all.gyp

 # 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': {
     # A hook that can be overridden in other repositories to add additional
     # compilation targets to 'All'.
     'app_targets%': [],
     # For Android-specific targets.
@@ skipping 474 matching lines @@
             '../mojo/mojo_nacl.gyp:monacl_codegen',
             '../mojo/mojo_nacl.gyp:monacl_sel',
             '../mojo/mojo_nacl.gyp:monacl_shell',
           ],
         }],
       ],
     }, # target_name: chromium_builder_tests
   ],
   'conditions': [
     # TODO(GYP): make gn_migration.gypi work unconditionally.
-    ['OS=="linux" and target_arch=="x64" and chromeos==0 and chromecast==0 and disable_nacl==0', {
+    ['OS=="win" or (OS=="linux" and target_arch=="x64" and chromeos==0 and chromecast==0 and disable_nacl==0)', {
       'includes': [
         'gn_migration.gypi',
       ],
     }],
     ['OS!="ios"', {
       'targets': [
         {
           'target_name': 'blink_tests',
           'type': 'none',
           'dependencies': [
@@ skipping 866 matching lines @@
           'dependencies': [
             '../ui/views/examples/examples.gyp:views_examples_with_content_exe',
             '../ui/views/views.gyp:views',
             '../ui/views/views.gyp:views_unittests',
           ],
         },  # target_name: macviews_builder
       ],  # targets
     }],  # os=='mac' and toolkit_views==1
   ],  # conditions
 }