Add a white Default-568h@2x.png placeholder in iOS unit tests bundles.

testing/gtest.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.
 
 {
   'targets': [
     {
       'target_name': 'gtest',
       'type': 'static_library',
       'sources': [
@@ skipping 68 matching lines @@
                     '<(DEPTH)/testing/gtest_ios/unittest-Info.plist',
                 },
                 'mac_bundle': 1,
                 'xcode_settings': {
                   'BUNDLE_ID_TEST_NAME':
                     '>!(echo ">(_target_name)" | sed -e "s/_//g")',
                   'INFOPLIST_FILE': '>(ios_unittest_info_plist_path)',
                 },
                 'mac_bundle_resources': [
                   '<(ios_unittest_info_plist_path)',
+                  '<(DEPTH)/testing/gtest_ios/Default-568h@2x.png',
                 ],
                 'mac_bundle_resources!': [
                   '<(ios_unittest_info_plist_path)',
                 ],
               }],
             ],
           },
         }],
         ['os_posix == 1', {
           'defines': [
@@ skipping 103 matching lines @@
     {
       'target_name': 'gtest_prod',
       'toolsets': ['host', 'target'],
       'type': 'none',
       'sources': [
         'gtest/include/gtest/gtest_prod.h',
       ],
     },
   ],
 }