WebKit recently has been changed to pass context as 1st argument.

lib/dom/scripts/systemnative.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 provides shared functionality for the systems to generate
 native binding from the IDL database."""
 
 import emitter
 import os
@@ skipping 921 matching lines @@
       invocation_template = emitter.Format(
           '        ExceptionCode ec = 0;\n'
           '$INVOCATION'
           '        if (UNLIKELY(ec)) {\n'
           '            exception = DartDOMWrapper::exceptionCodeToDartException(ec);\n'
           '            goto fail;\n'
           '        }\n',
           INVOCATION=invocation_template)
 
     if 'ImplementedBy' in attributes:
-      arguments.insert(0, 'receiver')
+      # FIXME: rather ugly way to solve the problem.
+      index = 1 if 'ScriptExecutionContext' == attributes.get('CallWith') else 0
+      arguments.insert(index, 'receiver')
       self._cpp_impl_includes.add('"%s.h"' % attributes['ImplementedBy'])
 
     return emitter.Format(invocation_template,
         FUNCTION_CALL='%s(%s)' % (function_expression, ', '.join(arguments)))
 
   def _TypeInfo(self, type_name):
     return self._system._type_registry.TypeInfo(type_name)
 
 
 def _GenerateCPPIncludes(includes):
@@ skipping 13 matching lines @@
 
 def _IsArgumentOptionalInWebCore(argument):
   return IsOptional(argument) and not 'Callback' in argument.ext_attrs
 
 def _ToWebKitName(name):
   name = name[0].lower() + name[1:]
   name = re.sub(r'^(hTML|uRL|jS|xML|xSLT)', lambda s: s.group(1).lower(),
                 name)
   return re.sub(r'^(create|exclusive)', lambda s: 'is' + s.group(1).capitalize(),
                 name)