Add a new 'format-webkitpy' command that will reformat code to the style guide.

Tools/Scripts/webkitpy/common/system/systemhost_mock.py

 # Copyright (c) 2011 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 33 matching lines @@
         self.user = MockUser()
         self.platform = MockPlatformInfo()
         if os_name:
             self.platform.os_name = os_name
         if os_version:
             self.platform.os_version = os_version
 
         # FIXME: Should this take pointers to the filesystem and the executive?
         self.workspace = MockWorkspace()
 
+        self.stdin = StringIO()
         self.stdout = StringIO()
         self.stderr = StringIO()
 
     def copy_current_environment(self):
         return Environment({"MOCK_ENVIRON_COPY": '1'})
 
     def print_(self, *args, **kwargs):
         sep = kwargs.get('sep', ' ')
         end = kwargs.get('end', '\n')
-        file = kwargs.get('file', None)
-        stderr = kwargs.get('stderr', False)
-
-        file = file or (self.stderr if stderr else self.stdout)
-        file.write(sep.join([str(arg) for arg in args]) + end)
+        stream = kwargs.get('stream', self.stdout)
+        stream.write(sep.join([str(arg) for arg in args]) + end)