IDL: Auto-declare implied methods only if not otherwise declared

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 366 matching lines @@
 
         def generated_iterator_method(name):
             return generated_method(
                 return_type=IdlType('Iterator'),
                 name=name,
                 extended_attributes=used_extended_attributes)
 
         iterator_method = generated_iterator_method('iterator')
 
         if interface.iterable or interface.maplike or interface.setlike:
-            methods.extend([
+            implicit_methods = [
                 generated_iterator_method('keys'),
                 generated_iterator_method('values'),
                 generated_iterator_method('entries'),
 
                 # void forEach(Function callback, [Default=Undefined] optional any thisArg)
                 generated_method(IdlType('void'), 'forEach',
                                  arguments=[generated_argument(IdlType('Function'), 'callback'),
                                             generated_argument(IdlType('any'), 'thisArg',
                                                                is_optional=True,
                                                                extended_attributes={'Default': 'Undefined'})],
                                  extended_attributes=forEach_extended_attributes),
-            ])
+            ]
+
+            methods_by_name = {}
+            for method in methods:
+                methods_by_name.setdefault(method['name'], []).append(method)
+
+            for implicit_method in implicit_methods:
+                if implicit_method['name'] in methods_by_name:
+                    # FIXME: Check that the existing method is compatible.
+                    continue
+                methods.append(implicit_method)
 
         # FIXME: maplike<> and setlike<> should also imply the presence of a
         # subset of keys(), values(), entries(), forEach(), has(), get(), add(),
         # set(), delete() and clear(), and a 'size' attribute.
 
     # Stringifier
     if interface.stringifier:
         stringifier = interface.stringifier
         stringifier_ext_attrs = stringifier.extended_attributes.copy()
         if stringifier.attribute:
@@ skipping 825 matching lines @@
     if str(idl_type) != 'boolean':
         raise Exception(
             'Only deleters with boolean type are allowed, but type is "%s"' %
             idl_type)
     extended_attributes = deleter.extended_attributes
     return {
         'is_custom': 'Custom' in extended_attributes,
         'is_raises_exception': 'RaisesException' in extended_attributes,
         'name': cpp_name(deleter),
     }