IDL: Support using nullable on any method return type

Source/bindings/scripts/idl_definitions.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 751 matching lines @@
     # interface type. We do not distinguish these, and just use the type name.
     if node_class in ['PrimitiveType', 'Typeref']:
         # unrestricted syntax: unrestricted double | unrestricted float
         is_unrestricted = node.GetProperty('UNRESTRICTED') or False
         return IdlType(node.GetName(), is_array=is_array, is_nullable=is_nullable, is_unrestricted=is_unrestricted)
     elif node_class == 'Any':
         return IdlType('any', is_array=is_array, is_nullable=is_nullable)
     elif node_class == 'Sequence':
         if is_array:
             raise ValueError('Arrays of sequences are not supported')
-        return sequence_node_to_type(node, is_nullable=is_nullable)
+        sequence_is_nullable = node.GetProperty('NULLABLE') or False
+        return sequence_node_to_type(node, is_nullable=sequence_is_nullable)
     elif node_class == 'UnionType':
         if is_array:
             raise ValueError('Arrays of unions are not supported')
         return union_type_node_to_idl_union_type(node, is_nullable=is_nullable)
     raise ValueError('Unrecognized node class: %s' % node_class)
 
 
 def sequence_node_to_type(node, is_nullable=False):
     children = node.GetChildren()
     if len(children) != 1:
@@ skipping 14 matching lines @@
     child_class = child.GetClass()
     if child_class != 'Type':
         raise ValueError('Unrecognized node class: %s' % child_class)
     return type_node_to_type(child)
 
 
 def union_type_node_to_idl_union_type(node, is_nullable=False):
     member_types = [type_node_to_type(member_type_node)
                     for member_type_node in node.GetChildren()]
     return IdlUnionType(member_types, is_nullable=is_nullable)