Better support for the case of typed arrays inheriting from other typed arrays.

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 378 matching lines @@
         generator.AddConstant(const)
 
     attributes = [attr for attr in interface.attributes
                   if attr.type.id != 'EventListener']
     for (getter, setter) in  _PairUpAttributes(attributes):
       for generator in generators:
         generator.AddAttribute(getter, setter)
 
     # The implementation should define an indexer if the interface directly
     # extends List.
-    element_type = MaybeListElementType(interface)
+    (element_type, requires_indexer) = ListImplementationInfo(
+          interface, self._database)
     if element_type:
       for generator in generators:
-        generator.AddIndexer(element_type)
+        if requires_indexer:
+          generator.AddIndexer(element_type)
+        else:
+          generator.AmendIndexer(element_type)
     # Group overloaded operations by id
     operationsById = {}
     for operation in interface.operations:
       if operation.id not in operationsById:
         operationsById[operation.id] = []
       operationsById[operation.id].append(operation)
 
     # Generate operations
     for id in sorted(operationsById.keys()):
       operations = operationsById[id]
@@ skipping 204 matching lines @@
 
   def AddSecondaryAttribute(self, interface, getter, setter):
     pass
 
   def AddSecondaryOperation(self, interface, info):
     pass
 
   def AddIndexer(self, element_type):
     pass
 
+  def AmendIndexer(sefl, element_type):
+    pass
+
   def AddTypedArrayConstructors(self, element_type):
     pass
 
   def AddOperation(self, info):
     pass
 
   def AddStaticOperation(self, info):
     pass
 
   def AddEventAttributes(self, event_attrs):
     pass