Add a native subtype of function that uses the native C++ class hierarchy to check if an element

Source/bindings/dart/gyp/dartium.gyp

 {
   'includes': [
     '../../../core/features.gypi',
     '../../../core/core.gypi',
     '../../../modules/modules.gypi',
     'overrides.gypi',
   ],
   'variables': {
     'dart_dir': '../../../../../../dart',
     'dart_lib_dir': '<(dart_dir)/sdk/lib',
@@ skipping 230 matching lines @@
       'actions': [
         {
           'action_name': 'generate_dart_bindings',
           'inputs': [
             'scripts/generate_dart_bindings.py',
             '<(idls_list_temp_file)',
             '<@(bindings_idl_files)',
             '<@(dart_html_lib_deps)',
           ],
           'outputs': [
+            '<(output_path)/DartWebkitClassIds.cpp',
             '<(output_path)/html_DartResolver.cpp',
             '<(output_path)/html_dartium.dart',
             '<(output_path)/indexed_db_DartResolver.cpp',
             '<(output_path)/indexed_db_dartium.dart',
             '<(output_path)/svg_DartResolver.cpp',
             '<(output_path)/svg_dartium.dart',
             '<(output_path)/web_audio_DartResolver.cpp',
             '<(output_path)/web_audio_dartium.dart',
             '<(output_path)/web_gl_DartResolver.cpp',
             '<(output_path)/web_gl_dartium.dart',
@@ skipping 45 matching lines @@
             '<(resources_dir)/DartSnapshot.bytes.template',
             '<(output_path)',
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)gen_snapshot<(EXECUTABLE_SUFFIX)',
             '<@(pure_libs)',
           ],
         },
       ],
     },
   ],
 }