IDL: Union type support for attributes

Source/bindings/scripts/v8_methods.py

 # Copyright (C) 2013 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
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 44 matching lines @@
 def use_local_result(method):
     extended_attributes = method.extended_attributes
     idl_type = method.idl_type
     return (has_extended_attribute_value(method, 'CallWith', 'ScriptState') or
             'ImplementedInPrivateScript' in extended_attributes or
             'RaisesException' in extended_attributes or
             idl_type.is_union_type or
             idl_type.is_explicit_nullable)
 
 
-def use_output_parameter_for_result(idl_type):
-    return idl_type.is_dictionary or idl_type.is_union_type
-
-
 def method_context(interface, method, is_visible=True):
     arguments = method.arguments
     extended_attributes = method.extended_attributes
     idl_type = method.idl_type
     is_static = method.is_static
     name = method.name
 
     idl_type.add_includes_for_type()
     this_cpp_value = cpp_value(interface, method, len(arguments))
 
@@ skipping 96 matching lines @@
             argument for argument in arguments
             if not argument.is_optional]),
         'only_exposed_to_private_script': is_only_exposed_to_private_script,
         'per_context_enabled_function': v8_utilities.per_context_enabled_function_name(method),  # [PerContextEnabled]
         'private_script_v8_value_to_local_cpp_value': idl_type.v8_value_to_local_cpp_value(
             extended_attributes, 'v8Value', 'cppValue', isolate='scriptState->isolate()', used_in_private_script=True),
         'property_attributes': property_attributes(method),
         'runtime_enabled_function': v8_utilities.runtime_enabled_function_name(method),  # [RuntimeEnabled]
         'should_be_exposed_to_script': not (is_implemented_in_private_script and is_only_exposed_to_private_script),
         'signature': 'v8::Local<v8::Signature>()' if is_static or 'DoNotCheckSignature' in extended_attributes else 'defaultSignature',
-        'use_output_parameter_for_result': use_output_parameter_for_result(idl_type),
+        'use_output_parameter_for_result': idl_type.use_output_parameter_for_result,
         'use_local_result': use_local_result(method),
         'v8_set_return_value': v8_set_return_value(interface.name, method, this_cpp_value),
         'v8_set_return_value_for_main_world': v8_set_return_value(interface.name, method, this_cpp_value, for_main_world=True),
         'visible': is_visible,
         'world_suffixes': ['', 'ForMainWorld'] if 'PerWorldBindings' in extended_attributes else [''],  # [PerWorldBindings],
     }
 
 
 def argument_context(interface, method, argument, index):
     extended_attributes = argument.extended_attributes
@@ skipping 107 matching lines @@
         if method.idl_type.name != 'void':
             cpp_arguments.append('&result')
     elif ('RaisesException' in method.extended_attributes or
         (method.is_constructor and
          has_extended_attribute_value(interface, 'RaisesException', 'Constructor'))):
         cpp_arguments.append('exceptionState')
 
     # If a method returns an IDL dictionary or union type, the return value is
     # passed as an argument to impl classes.
     idl_type = method.idl_type
-    if idl_type and use_output_parameter_for_result(idl_type):
+    if idl_type and idl_type.use_output_parameter_for_result:
         cpp_arguments.append('result')
 
     if method.name == 'Constructor':
         base_name = 'create'
     elif method.name == 'NamedConstructor':
         base_name = 'createForJSConstructor'
     elif 'ImplementedInPrivateScript' in method.extended_attributes:
         base_name = '%sMethod' % method.name
     else:
         base_name = v8_utilities.cpp_name(method)
@@ skipping 92 matching lines @@
 
 IdlOperation.returns_promise = property(method_returns_promise)
 
 
 def argument_conversion_needs_exception_state(method, argument):
     idl_type = argument.idl_type
     return (idl_type.v8_conversion_needs_exception_state or
             argument.is_variadic or
             (method.returns_promise and (idl_type.is_string_type or
                                          idl_type.is_enum)))