Update union conversion algorithm

third_party/WebKit/Source/core/core.gyp

 #
 # Copyright (C) 2009 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 478 matching lines @@
       ],
       'include_dirs': [
         'testing',
         'testing/v8',
       ],
       'sources': [
         # Note: file list duplicated in GN build.
         '<@(generated_core_testing_dictionary_files)',
         '<@(webcore_testing_files)',
         '<@(generated_bindings_core_testing_files)',
+        '<@(bindings_core_v8_generated_testing_union_type_files)',
       ],
       'sources/': [
         ['exclude', 'testing/js'],
       ],
       'conditions': [
         ['component!="shared_library"', {
           'dependencies': [
             'webcore',
             'webcore_generated',
           ],
@@ skipping 152 matching lines @@
                 'layout/LayoutThemeAndroid.cpp',
                 'layout/LayoutThemeAndroid.h',
               ],
             }],
           ],
         }],
       ],
     },
   ],  # targets
 }