Convert sbox_unittests to run exclusively on Swarming

build/gn_migration.gypi

 # Copyright (c) 2015 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.
 
 # This file defines five targets that we are using to track the progress of the
 # GYP->GN migration:
 #
 # 'both_gn_and_gyp' lists what GN is currently capable of building and should
 # match the 'both_gn_and_gyp' target in //BUILD.gn.
 #
@@ skipping 551 matching lines @@
               ],
             }],
             ['OS=="mac"', {
               'dependencies': [
                 '../sandbox/sandbox.gyp:sandbox_mac_unittests_run',
               ],
             }],
             ['OS=="win"', {
               'dependencies': [
                 '../sandbox/sandbox.gyp:sbox_integration_tests',
+                '../sandbox/sandbox.gyp:sbox_unittests',
               ],
             }],
             ['use_ash==1', {
               'dependencies': [
                 '../ash/ash.gyp:ash_unittests_run',
               ],
             }],
             ['use_aura==1', {
               'dependencies': [
                 '../ui/aura/aura.gyp:aura_unittests_run',
@@ skipping 129 matching lines @@
           'dependencies': [
             # TODO(GYP): All of these targets need to be ported over.
             '../components/components.gyp:policy_win64',
           ]
         }],
       ],
     },
   ]
 }