Revert "Revert "Rework Element constructors""

lib/dom/scripts/dartgenerator.py

 #!/usr/bin/python
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """This module generates Dart APIs from the IDL database."""
 
 import emitter
 import idlnode
 import logging
@@ skipping 334 matching lines @@
       for parent in parents:
         if IsDartCollectionType(parent.type.id):
           result.append(parent.type.id)
           continue
         if self._database.HasInterface(parent.type.id):
           parent_interface = self._database.GetInterface(parent.type.id)
           result.append(parent_interface)
           walk(parent_interface.parents)
 
     result = []
-    walk(interface.parents[1:])
+    if interface.parents:
+      parent = interface.parents[0]
+      if IsPureInterface(parent.type.id):
+        walk(interface.parents)
+      else:
+        walk(interface.parents[1:])
     return result;
 
 
   def _CollectExceptions(self, interfaces):
     """Returns the names of all exception classes raised."""
     exceptions = set()
     for interface in interfaces:
       for attribute in interface.attributes:
         if attribute.get_raises:
           exceptions.add(attribute.get_raises.id)
@@ skipping 116 matching lines @@
     pass
 
   def AddOperation(self, info):
     pass
 
   def AddStaticOperation(self, info):
     pass
 
   def AddEventAttributes(self, event_attrs):
     pass