Introduce infrastructure for tracing ScriptWrappables.

third_party/WebKit/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 127 matching lines @@
             # FIXME: properly should be:
             # 'cpp_type': set_wrapper_reference_to_argument.idl_type.cpp_type_args(raw_type=True),
             # (if type is non-wrapper type like NodeFilter, normally RefPtr)
             # Raw pointers faster though, and NodeFilter hacky anyway.
             'cpp_type': set_wrapper_reference_to_argument.idl_type.implemented_as + '*',
             'idl_type': set_wrapper_reference_to_argument.idl_type,
             'v8_type': v8_types.v8_type(set_wrapper_reference_to_argument.idl_type.name),
         }
         set_wrapper_reference_to['idl_type'].add_includes_for_type()
 
-    # [SetWrapperReferenceFrom]
+    # [Custom=VisitDOMWrapper]
     has_visit_dom_wrapper = (
         has_extended_attribute_value(interface, 'Custom', 'VisitDOMWrapper') or
         set_wrapper_reference_from or set_wrapper_reference_to)
 
+    # [TraceWrapperReferences]
+    trace_wrapper_references = extended_attribute_value_as_list(interface, 'TraceWrapperReferences')
+    if trace_wrapper_references:
+        includes.add('bindings/core/v8/ScriptWrappableVisitor.h')
+
     wrapper_class_id = ('NodeClassId' if inherits_interface(interface.name, 'Node') else 'ObjectClassId')
 
     v8_class_name = v8_utilities.v8_class_name(interface)
     cpp_class_name = cpp_name(interface)
     cpp_class_name_or_partial = cpp_name_or_partial(interface)
     v8_class_name_or_partial = v8_utilities.v8_class_name_or_partial(interface)
 
     context = {
         'cpp_class': cpp_class_name,
         'cpp_class_or_partial': cpp_class_name_or_partial,
         'event_target_inheritance': 'InheritFromEventTarget' if is_event_target else 'NotInheritFromEventTarget',
         'is_gc_type': True,
         # FIXME: Remove 'EventTarget' special handling, http://crbug.com/383699
         'has_access_check_callbacks': (is_check_security and
                                        interface.name != 'Window' and
                                        interface.name != 'EventTarget'),
         'has_custom_legacy_call_as_function': has_extended_attribute_value(interface, 'Custom', 'LegacyCallAsFunction'),  # [Custom=LegacyCallAsFunction]
         'has_partial_interface': len(interface.partial_interfaces) > 0,
         'has_visit_dom_wrapper': has_visit_dom_wrapper,
+        'trace_wrapper_references': trace_wrapper_references,
         'header_includes': header_includes,
         'interface_name': interface.name,
         'is_array_buffer_or_view': is_array_buffer_or_view,
         'is_check_security': is_check_security,
         'is_event_target': is_event_target,
         'is_exception': interface.is_exception,
         'is_global': is_global,
         'is_node': inherits_interface(interface.name, 'Node'),
         'is_partial': interface.is_partial,
         'is_typed_array_type': is_typed_array_type,
-        'lifetime': 'Dependent' if (has_visit_dom_wrapper or is_dependent_lifetime) else 'Independent',
+        'lifetime': 'Dependent' if (has_visit_dom_wrapper or trace_wrapper_references or is_dependent_lifetime) else 'Independent',
         'measure_as': v8_utilities.measure_as(interface, None),  # [MeasureAs]
         'origin_trial_enabled_function': v8_utilities.origin_trial_enabled_function_name(interface, None),
         'parent_interface': parent_interface,
         'pass_cpp_type': cpp_name(interface) + '*',
         'active_scriptwrappable': active_scriptwrappable,
         'runtime_enabled_function': runtime_enabled_function_name(interface),  # [RuntimeEnabled]
         'set_wrapper_reference_from': set_wrapper_reference_from,
         'set_wrapper_reference_to': set_wrapper_reference_to,
         'v8_class': v8_class_name,
         'v8_class_or_partial': v8_class_name_or_partial,
@@ skipping 1186 matching lines @@
 
     extended_attributes = deleter.extended_attributes
     idl_type = deleter.idl_type
     is_call_with_script_state = v8_utilities.has_extended_attribute_value(deleter, 'CallWith', 'ScriptState')
     return {
         'is_call_with_script_state': is_call_with_script_state,
         'is_custom': 'Custom' in extended_attributes,
         'is_raises_exception': 'RaisesException' in extended_attributes,
         'name': cpp_name(deleter),
     }