Restructure handling of list type extended attributes

Source/bindings/scripts/v8_interface.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 # coding=utf-8
 #
 # 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 28 matching lines @@
 import idl_definitions
 from idl_definitions import IdlOperation
 import idl_types
 from idl_types import IdlType, inherits_interface
 import v8_attributes
 from v8_globals import includes
 import v8_methods
 import v8_types
 from v8_types import cpp_ptr_type, cpp_template_type
 import v8_utilities
-from v8_utilities import capitalize, conditional_string, cpp_name, gc_type, has_extended_attribute_value, runtime_enabled_function_name
+from v8_utilities import (capitalize, conditional_string, cpp_name, gc_type,
+                          has_extended_attribute_value, runtime_enabled_function_name,
+                          extended_attribute_value_as_list)
 
 
 INTERFACE_H_INCLUDES = frozenset([
     'bindings/core/v8/ScriptWrappable.h',
     'bindings/core/v8/V8Binding.h',
     'bindings/core/v8/V8DOMWrapper.h',
     'bindings/core/v8/WrapperTypeInfo.h',
     'platform/heap/Handle.h',
 ])
 INTERFACE_CPP_INCLUDES = frozenset([
@@ skipping 61 matching lines @@
         # Raw pointers faster though, and NodeFilter hacky anyway.
         'cpp_type': argument.idl_type.implemented_as + '*',
         'idl_type': argument.idl_type,
         'v8_type': v8_types.v8_type(argument.idl_type.name),
     } for argument in extended_attributes.get('SetWrapperReferenceTo', [])]
     for set_wrapper_reference_to in set_wrapper_reference_to_list:
         set_wrapper_reference_to['idl_type'].add_includes_for_type()
 
     # [SpecialWrapFor]
     if 'SpecialWrapFor' in extended_attributes:
-        special_wrap_for = extended_attributes['SpecialWrapFor'].split('|')
+        special_wrap_for = extended_attribute_value_as_list(interface, 'SpecialWrapFor')
     else:
         special_wrap_for = []
     for special_wrap_interface in special_wrap_for:
         v8_types.add_includes_for_interface(special_wrap_interface)
 
     # [Custom=Wrap], [SetWrapperReferenceFrom]
     has_visit_dom_wrapper = (
         has_extended_attribute_value(interface, 'Custom', 'VisitDOMWrapper') or
         reachable_node_function or
         set_wrapper_reference_to_list)
@@ skipping 972 matching lines @@
         deleter = next(
             method
             for method in interface.operations
             if ('deleter' in method.specials and
                 len(method.arguments) == 1 and
                 str(method.arguments[0].idl_type) == 'DOMString'))
     except StopIteration:
         return None
 
     return property_deleter(deleter)