Support optional, non-defaulted constructor arguments.

Source/bindings/scripts/v8_utilities.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 95 matching lines @@
                         for enum_value in idl_type.enum_values])
 IdlType.enum_validation_expression = property(enum_validation_expression)
 
 
 def scoped_name(interface, definition, base_name):
     # partial interfaces are implemented as separate classes, with their members
     # implemented as static member functions
     partial_interface_implemented_as = definition.extended_attributes.get('PartialInterfaceImplementedAs')
     if partial_interface_implemented_as:
         return '%s::%s' % (partial_interface_implemented_as, base_name)
-    if definition.is_static:
+    if (definition.is_static or
+        definition.name in ('Constructor', 'NamedConstructor')):
         return '%s::%s' % (cpp_name(interface), base_name)
     return 'impl->%s' % base_name
 
 
 def v8_class_name(interface):
     return v8_types.v8_type(interface.name)
 
 
 ################################################################################
 # Specific extended attributes
@@ skipping 106 matching lines @@
 
     The returned function checks if a method/attribute is enabled.
     Given extended attribute RuntimeEnabled=FeatureName, return:
         RuntimeEnabledFeatures::{featureName}Enabled
     """
     extended_attributes = definition_or_member.extended_attributes
     if 'RuntimeEnabled' not in extended_attributes:
         return None
     feature_name = extended_attributes['RuntimeEnabled']
     return 'RuntimeEnabledFeatures::%sEnabled' % uncapitalize(feature_name)