IDL: Generate trace() method in union container types when required

Source/bindings/scripts/v8_union.py

Index: Source/bindings/scripts/v8_union.py
diff --git a/Source/bindings/scripts/v8_union.py b/Source/bindings/scripts/v8_union.py
index fab726e59ebf04553547ce817cb35ad7512580e8..57e73b94f95c2b5e616ac9968bcf454f90421c43 100644
--- a/Source/bindings/scripts/v8_union.py
+++ b/Source/bindings/scripts/v8_union.py
@@ -65,6 +65,7 @@ def container_context(union_type, interfaces_info):
         'dictionary_type': dictionary_type,
         'interface_types': interface_types,
         'members': members,
+        'needs_trace': any(member['is_traceable'] for member in members),
         'numeric_type': numeric_type,
         'string_type': string_type,
     }
@@ -83,6 +84,8 @@ def member_context(member, interfaces_info):
         'cpp_value_to_v8_value': member.cpp_value_to_v8_value(
             cpp_value='impl.getAs%s()' % member.name, isolate='isolate',
             creation_context='creationContext'),
+        'is_traceable': (member.is_garbage_collected or

[sof, 2014/10/31 07:30:12]

Might be worth lifting out into a helper in v8_types, as it is used elsewhere
also?

[Jens Widell, 2014/10/31 07:48:46]

Yes. I'll follow up with that.

+                         member.is_will_be_garbage_collected),
         'rvalue_cpp_type': member.cpp_type_args(used_as_rvalue_type=True),
         'specific_type_enum': 'SpecificType' + member.name,
         'type_name': member.name,