Drop [TypeChecking=Nullable]; deduce from attribute type instead

Source/bindings/scripts/v8_attributes.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 49 matching lines @@
                          extended_attributes['Custom'] in [None, 'Setter'])
     # [CustomElementCallbacks], [Reflect]
     is_custom_element_callbacks = 'CustomElementCallbacks' in extended_attributes
     is_reflect = 'Reflect' in extended_attributes
     if is_custom_element_callbacks or is_reflect:
         includes.add('core/dom/custom/CustomElementCallbackDispatcher.h')
     # [PerWorldBindings]
     if 'PerWorldBindings' in extended_attributes:
         assert idl_type.is_wrapper_type or 'LogActivity' in extended_attributes, '[PerWorldBindings] should only be used with wrapper types: %s.%s' % (interface.name, attribute.name)
     # [TypeChecking]
-    has_type_checking_nullable = (
-        (has_extended_attribute_value(interface, 'TypeChecking', 'Nullable') or
-         has_extended_attribute_value(attribute, 'TypeChecking', 'Nullable')) and
-         idl_type.is_wrapper_type)
     has_type_checking_unrestricted = (
         (has_extended_attribute_value(interface, 'TypeChecking', 'Unrestricted') or
          has_extended_attribute_value(attribute, 'TypeChecking', 'Unrestricted')) and
          idl_type.name in ('Float', 'Double'))
 
     if (base_idl_type == 'EventHandler' and
         interface.name in ['Window', 'WorkerGlobalScope'] and
         attribute.name == 'onerror'):
         includes.add('bindings/v8/V8ErrorHandler.h')
 
     context = {
         'access_control_list': access_control_list(attribute),
         'activity_logging_world_list_for_getter': v8_utilities.activity_logging_world_list(attribute, 'Getter'),  # [ActivityLogging]
         'activity_logging_world_list_for_setter': v8_utilities.activity_logging_world_list(attribute, 'Setter'),  # [ActivityLogging]
         'activity_logging_include_old_value_for_setter': 'LogPreviousValue' in extended_attributes,  # [ActivityLogging]
         'activity_logging_world_check': v8_utilities.activity_logging_world_check(attribute),  # [ActivityLogging]
         'cached_attribute_validation_method': extended_attributes.get('CachedAttribute'),
         'conditional_string': v8_utilities.conditional_string(attribute),
         'constructor_type': idl_type.constructor_type_name
                             if is_constructor_attribute(attribute) else None,
         'cpp_name': cpp_name(attribute),
         'cpp_type': idl_type.cpp_type,
         'cpp_value_to_v8_value': idl_type.cpp_value_to_v8_value(cpp_value='original', creation_context='info.Holder()'),
         'deprecate_as': v8_utilities.deprecate_as(attribute),  # [DeprecateAs]
         'enum_validation_expression': idl_type.enum_validation_expression,
         'has_custom_getter': has_custom_getter,
         'has_custom_setter': has_custom_setter,
-        'has_type_checking_nullable': has_type_checking_nullable,
         'has_type_checking_unrestricted': has_type_checking_unrestricted,
         'idl_type': str(idl_type),  # need trailing [] on array for Dictionary::ConversionContext::setConversionType
         'is_call_with_execution_context': v8_utilities.has_extended_attribute_value(attribute, 'CallWith', 'ExecutionContext'),
         'is_call_with_script_state': v8_utilities.has_extended_attribute_value(attribute, 'CallWith', 'ScriptState'),
         'is_check_security_for_node': is_check_security_for_node,
         'is_custom_element_callbacks': is_custom_element_callbacks,
         'is_expose_js_accessors': 'ExposeJSAccessors' in extended_attributes,
         'is_getter_raises_exception':  # [RaisesException]
             'RaisesException' in extended_attributes and
             extended_attributes['RaisesException'] in (None, 'Getter'),
         'is_initialized_by_event_constructor':
             'InitializedByEventConstructor' in extended_attributes,
         'is_keep_alive_for_gc': is_keep_alive_for_gc(interface, attribute),
-        'is_nullable': attribute.idl_type.is_nullable,
+        'is_nullable': idl_type.is_nullable,
+        'is_nullable_simple': idl_type.is_nullable and idl_type.is_wrapper_type,  # null value maps to C++ null pointer
         'is_partial_interface_member':
             'PartialInterfaceImplementedAs' in extended_attributes,
         'is_per_world_bindings': 'PerWorldBindings' in extended_attributes,
         'is_read_only': attribute.is_read_only,
         'is_reflect': is_reflect,
         'is_replaceable': 'Replaceable' in attribute.extended_attributes,
         'is_static': attribute.is_static,
         'is_url': 'URL' in extended_attributes,
         'is_unforgeable': 'Unforgeable' in extended_attributes,
         'measure_as': v8_utilities.measure_as(attribute),  # [MeasureAs]
@@ skipping 74 matching lines @@
     getter_name = scoped_name(interface, attribute, this_getter_base_name)
 
     arguments.extend(v8_utilities.call_with_arguments(
         attribute.extended_attributes.get('CallWith')))
     # Members of IDL partial interface definitions are implemented in C++ as
     # static member functions, which for instance members (non-static members)
     # take *impl as their first argument
     if ('PartialInterfaceImplementedAs' in attribute.extended_attributes and
         not attribute.is_static):
         arguments.append('*impl')
-    if attribute.idl_type.is_nullable and not context['has_type_checking_nullable']:
+    if attribute.idl_type.is_nullable and not context['is_nullable_simple']:
         arguments.append('isNull')
     if context['is_getter_raises_exception']:
         arguments.append('exceptionState')
     return '%s(%s)' % (getter_name, ', '.join(arguments))
 
 
 CONTENT_ATTRIBUTE_GETTER_NAMES = {
     'boolean': 'fastHasAttribute',
     'long': 'getIntegralAttribute',
     'unsigned long': 'getUnsignedIntegralAttribute',
@@ skipping 71 matching lines @@
         extended_attributes['RaisesException'] in [None, 'Setter'])
     # [TypeChecking=Interface]
     has_type_checking_interface = (
         (has_extended_attribute_value(interface, 'TypeChecking', 'Interface') or
          has_extended_attribute_value(attribute, 'TypeChecking', 'Interface')) and
         idl_type.is_wrapper_type)
 
     context.update({
         'has_setter_exception_state':
             is_setter_raises_exception or has_type_checking_interface or
-            context['has_type_checking_nullable'] or
             context['has_type_checking_unrestricted'] or
             idl_type.may_raise_exception_on_conversion,
         'has_type_checking_interface': has_type_checking_interface,
         'is_setter_call_with_execution_context': v8_utilities.has_extended_attribute_value(
             attribute, 'SetterCallWith', 'ExecutionContext'),
         'is_setter_raises_exception': is_setter_raises_exception,
         'v8_value_to_local_cpp_value': idl_type.v8_value_to_local_cpp_value(
             extended_attributes, 'v8Value', 'cppValue'),
     })
 
@@ skipping 119 matching lines @@
     lambda self: strip_suffix(self.base_type, 'Constructor'))
 
 
 def is_constructor_attribute(attribute):
     # FIXME: replace this with [ConstructorAttribute] extended attribute
     return attribute.idl_type.base_type.endswith('Constructor')
 
 
 def constructor_getter_context(interface, attribute, context):
     context['needs_constructor_getter_callback'] = context['measure_as'] or context['deprecate_as']