Introduce ES6 iterator for DOM objects.

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 738 matching lines @@
         'INSIDE_BLINK',
       ],
       'include_dirs': [
         '<(bindings_core_v8_dir)',  # FIXME: Remove once http://crbug.com/236119 is fixed.
         'testing',
         'testing/v8',
       ],
       'sources': [
         # Note: file list duplicated in GN build.
         '<@(webcore_testing_files)',
+        '<@(bindings_core_v8_custom_testing_files)',
         '<(bindings_core_v8_output_dir)/V8GarbageCollectedScriptWrappable.cpp',
         '<(bindings_core_v8_output_dir)/V8GarbageCollectedScriptWrappable.h',
         '<(bindings_core_v8_output_dir)/V8GCObservation.cpp',
         '<(bindings_core_v8_output_dir)/V8GCObservation.h',
         '<(bindings_core_v8_output_dir)/V8PrivateScriptTest.cpp',
         '<(bindings_core_v8_output_dir)/V8PrivateScriptTest.h',
         '<(bindings_core_v8_output_dir)/V8TypeConversions.cpp',
         '<(bindings_core_v8_output_dir)/V8TypeConversions.h',
         '<(bindings_core_v8_output_dir)/V8Internals.cpp',
         '<(bindings_core_v8_output_dir)/V8Internals.h',
@@ skipping 11 matching lines @@
         '<(bindings_core_v8_output_dir)/V8LayerRectList.h',
         '<(bindings_core_v8_output_dir)/V8RefCountedScriptWrappable.cpp',
         '<(bindings_core_v8_output_dir)/V8RefCountedScriptWrappable.h',
       ],
       'sources/': [
         ['exclude', 'testing/js'],
       ],
     },
   ],  # targets
 }