Fixes for Blink roll to r151189

tools/dom/scripts/idlparser.py

 #!/usr/bin/python
 # Copyright (c) 2011, 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.
 
 import re
 import subprocess
 import tempfile
 
 from pegparser import *
@@ skipping 245 matching lines @@
     def _ExceptionMember():
       return OR(Const, ExceptionField, ExtAttrs)
 
     def ExceptionField():
       return [Type, Id, ';']
 
     # Types:
     def Type():
       return _Type
 
+    def UnionType():
+      return ['(', Type, 'or', Type, ')']
+
     def ReturnType():
-      return OR(VoidType, _Type)
+      return OR(VoidType, _Type, UnionType)
 
     def InterfaceType():
       return ScopedName
 
     def ArrayModifiers():
       return re.compile(r'(\[\])+')
 
     def _Type():
       return OR(
           [OR(AnyType, ObjectType), MAYBE([ArrayModifiers, MAYBE(Nullable)])],
@@ skipping 138 matching lines @@
     Args:
       content -- text to parse.
       defines -- an array of pre-processor defines.
       includePaths -- an array of path strings used by the
         gcc pre-processor.
     """
     if self._syntax == WEBKIT_SYNTAX:
       content = self._pre_process(content, defines, includePaths)
 
     return self._pegparser.parse(content)