Fix idlparser.py: const should always go after ext attrs.

client/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 126 matching lines @@
 
     def ImplStmtImplemented():
       return ScopedName
 
     # Constants:
     def Const():
       return syntax_switch(
         # Web IDL:
         [MAYBE(ExtAttrs), 'const', Type, Id, '=', ConstExpr, ';'],
         # WebKit:
-        [OR(['const', MAYBE(ExtAttrs)], [MAYBE(ExtAttrs), 'const']),
-         Type, Id, '=', ConstExpr, ';'],
+        [MAYBE(ExtAttrs), 'const', Type, Id, '=', ConstExpr, ';'],
         # FremontCut:
         [MAYBE(_Annotations), MAYBE(ExtAttrs), 'const', Type, Id, '=',
          ConstExpr, ';'])
 
     def ConstExpr():
       return OR(_BooleanLiteral,
             _IntegerLiteral,
             _FloatLiteral)
 
     def _BooleanLiteral():
@@ skipping 275 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)