IDL: Generate union type containers

Source/bindings/scripts/compute_interfaces_info_individual.py

Index: Source/bindings/scripts/compute_interfaces_info_individual.py
diff --git a/Source/bindings/scripts/compute_interfaces_info_individual.py b/Source/bindings/scripts/compute_interfaces_info_individual.py
index eb5a2363475486795225f10ce39ec9eb9620414c..ef36111441a1a593167b1760450b095a684f287f 100755
--- a/Source/bindings/scripts/compute_interfaces_info_individual.py
+++ b/Source/bindings/scripts/compute_interfaces_info_individual.py
@@ -197,8 +197,8 @@ class InterfaceInfoCollector(object):
         else:
             raise Exception('IDL file must contain one interface or dictionary')
 
-        self.union_types.update(
-            collect_union_types_from_definitions(definitions))
+        this_union_types = collect_union_types_from_definitions(definitions)
+        self.union_types.update(this_union_types)
 
         extended_attributes = definition.extended_attributes
         implemented_as = extended_attributes.get('ImplementedAs')
@@ -220,6 +220,7 @@ class InterfaceInfoCollector(object):
         interface_info.update({
             'extended_attributes': extended_attributes,
             'full_path': full_path,
+            'has_union_types': bool(this_union_types),
             'implemented_as': implemented_as,
             'implemented_by_interfaces': left_interfaces,
             'implements_interfaces': right_interfaces,