Reimplement [PutForwards] per spec

third_party/WebKit/Source/bindings/scripts/v8_attributes.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 360 matching lines @@
              base_idl_type in ['EventTarget', 'Window'] or
              base_idl_type.startswith(('HTML', 'SVG')))))
 
 
 ################################################################################
 # Setter
 ################################################################################
 
 def setter_context(interface, attribute, interfaces, context):
     if 'PutForwards' in attribute.extended_attributes:
-        # Use target interface and attribute in place of original interface and
-        # attribute from this point onwards.
+        # Make sure the target interface and attribute exist.
         target_interface_name = attribute.idl_type.base_type
         target_attribute_name = attribute.extended_attributes['PutForwards']
         interface = interfaces[target_interface_name]
         try:
-            attribute = next(candidate
-                             for candidate in interface.attributes
-                             if candidate.name == target_attribute_name)
+            next(candidate
+                 for candidate in interface.attributes
+                 if candidate.name == target_attribute_name)
         except StopIteration:
             raise Exception('[PutForward] target not found:\n'
                             'Attribute "%s" is not present in interface "%s"' %
                             (target_attribute_name, target_interface_name))
+        context['target_attribute_name'] = target_attribute_name
+        return
 
     if ('Replaceable' in attribute.extended_attributes):
         context['cpp_setter'] = 'v8CallBoolean(info.Holder()->CreateDataProperty(info.GetIsolate()->GetCurrentContext(), propertyName, v8Value))'
         return
 
     extended_attributes = attribute.extended_attributes
     idl_type = attribute.idl_type
 
     # [RaisesException], [RaisesException=Setter]
     is_setter_raises_exception = (
@@ skipping 153 matching lines @@
     lambda self: strip_suffix(self.base_type, 'Constructor'))
 
 
 def is_constructor_attribute(attribute):
     # FIXME: replace this with [ConstructorAttribute] extended attribute
     return attribute.idl_type.name.endswith('Constructor')
 
 
 def update_constructor_attribute_context(interface, attribute, context):
     context['needs_constructor_getter_callback'] = context['measure_as'] or context['deprecate_as']