Drop isindex from HTMLTagNames.

Source/build/scripts/make_element_type_helpers.py

 #!/usr/bin/env python
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import sys
 from collections import defaultdict
 
 import hasher
 import in_generator
@@ skipping 24 matching lines @@
         'fallbackJSInterfaceName': '',
     }
     filters = {
         'hash': hasher.hash,
     }
 
     def __init__(self, in_file_path):
         super(MakeElementTypeHelpersWriter, self).__init__(in_file_path)
 
         self.namespace = self.in_file.parameters['namespace'].strip('"')
+        self.fallbackInterface = self.in_file.parameters['fallbackInterfaceName'].strip('"')
 
         assert self.namespace, 'A namespace is required.'
 
         self._outputs = {
             (self.namespace + "ElementTypeHelpers.h"): self.generate_helper_header,
         }
 
         self._template_context = {
             'namespace': self.namespace,
             'tags': self.in_file.name_dictionaries,
         }
 
         tags = self._template_context['tags']
         interface_counts = defaultdict(int)
         for tag in tags:
             tag['interface'] = self._interface(tag)
             interface_counts[tag['interface']] += 1
 
         for tag in tags:
-            tag['multipleTagNames'] = interface_counts[tag['interface']] > 1
+            tag['multipleTagNames'] = (interface_counts[tag['interface']] > 1 or tag['interface'] == self.fallbackInterface)
 
     @template_expander.use_jinja("ElementTypeHelpers.h.tmpl", filters=filters)
     def generate_helper_header(self):
         return self._template_context
 
     def _interface(self, tag):
         if tag['interfaceName']:
             return tag['interfaceName']
         name = name_utilities.upper_first(tag['name'])
         # FIXME: We shouldn't hard-code HTML here.
         if name == 'HTML':
             name = 'Html'
         dash = name.find('-')
         while dash != -1:
             name = name[:dash] + name[dash + 1].upper() + name[dash + 2:]
             dash = name.find('-')
         return '%s%sElement' % (self.namespace, name)
 
 if __name__ == "__main__":
     in_generator.Maker(MakeElementTypeHelpersWriter).main(sys.argv)