Update union conversion algorithm

third_party/WebKit/Source/bindings/core/v8/generated.gyp

 # Copyright 2014 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.
 
 # Generate IDL bindings for core, plus aggregate bindings files.
 #
 # Design doc: http://www.chromium.org/developers/design-documents/idl-build
 
 {
   'includes': [
@@ skipping 139 matching lines @@
         '<@(core_testing_dictionary_idl_files)',
         '<@(idl_lexer_parser_files)',
         '<@(idl_cache_files)',
         '<@(idl_compiler_files)',
         '<(bindings_dir)/IDLExtendedAttributes.txt',
         '<(bindings_modules_output_dir)/InterfacesInfoOverall.pickle',
         '<(bindings_core_output_dir)/ComponentInfoCore.pickle',
       ],
       'outputs': [
         '<@(bindings_core_v8_generated_union_type_files)',
+        '<@(bindings_core_v8_generated_testing_union_type_files)',
         '<@(generated_core_dictionary_files)',
         '<@(generated_core_testing_dictionary_files)',
       ],
       'action': [
         'python',
         '<(bindings_scripts_dir)/idl_compiler.py',
         '--cache-dir',
         '<(bindings_scripts_output_dir)',
         '--output-dir',
         '<(bindings_core_v8_output_dir)',
@@ skipping 18 matching lines @@
     'type': 'none',
     'dependencies': [
       'bindings_core_impl_generated',
       'bindings_core_v8_generated_aggregate',
       'bindings_core_v8_generated_individual',
     ],
   },
 ################################################################################
   ],  # targets
 }