Minor refactoring.

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 665 matching lines @@
       raises_exceptions = True
       requires_v8_scope = True
       requires_stack_info = True
       self._cpp_impl_includes.add('"ScriptArguments.h"')
       self._cpp_impl_includes.add('"ScriptCallStack.h"')
       cpp_arguments = ['scriptArguments', 'scriptCallStack']
 
     if ext_attrs.get('CallWith') == 'ScriptExecutionContext':
       raises_exceptions = True
       requires_script_execution_context = True
+      cpp_arguments = ['context']
+
+    if 'ImplementedBy' in ext_attrs:
+      assert needs_receiver
+      cpp_arguments.append('receiver')
+      self._cpp_impl_includes.add('"%s.h"' % ext_attrs['ImplementedBy'])
 
     if 'NamedConstructor' in ext_attrs:
       raises_exceptions = True
       requires_dom_window = True
       self._cpp_impl_includes.add('"DOMWindow.h"')
       cpp_arguments = ['document']
 
     if 'Reflect' in ext_attrs:
       cpp_arguments = [self._GenerateWebCoreReflectionAttributeName(node)]
 
@@ skipping 215 matching lines @@
       arguments.append('ec')
       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')
-      self._cpp_impl_includes.add('"%s.h"' % attributes['ImplementedBy'])
-
-    if attributes.get('CallWith') == 'ScriptExecutionContext':
-      arguments.insert(0, 'context')
-
     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):
   return ''.join(['#include %s\n' % include for include in sorted(includes)])
 
@@ skipping 11 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)