Add support in generate scripts to handle Conditional

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
 import name_utilities
 import template_expander
 
 from in_file import InFile
 
 
 def _symbol(tag):
     # FIXME: Remove this special case for the ugly x-webkit-foo attributes.
     if tag['name'].startswith('-webkit-'):
         return tag['name'].replace('-', '_')[1:]
     return name_utilities.cpp_name(tag).replace('-', '_')
 
 class MakeElementTypeHelpersWriter(in_generator.Writer):
     defaults = {
-        'interfaceName': None,
-        'noConstructor': None,
-        'noTypeHelpers': None,
+        'Conditional': None,
         'ImplementedAs': None,
         'JSInterfaceName': None,
         'constructorNeedsCreatedByParser': None,
         'constructorNeedsFormElement': None,
         'contextConditional': None,
         'interfaceName': None,
         'noConstructor': None,
+        'noConstructor': None,
+        'noTypeHelpers': None,
         'runtimeEnabled': None,
     }
     default_parameters = {
         'attrsNullNamespace': None,
+        'fallbackInterfaceName': '',
         'namespace': '',
         'namespacePrefix': '',
         'namespaceURI': '',
-        'fallbackInterfaceName': '',
         'fallbackJSInterfaceName': '',
     }
     filters = {
+        'enable_conditional': name_utilities.enable_conditional_if_endif,
         'hash': hasher.hash,
         'symbol': _symbol,
     }
 
     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('"')
 
@@ skipping 29 matching lines @@
         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)