Use underscores to separate words in filenames in webkitpy.

third_party/WebKit/Tools/Scripts/webkitpy/formatter/main.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import argparse
 import lib2to3.refactor
 
-from webkitpy.common.system.systemhost import SystemHost
+from webkitpy.common.system.system_host import SystemHost
 from webkitpy.thirdparty import autopep8
 
 
 def parse_args(args=None):
     parser = argparse.ArgumentParser()
     parser.add_argument('--chromium', action='store_const', dest='style', const='chromium', default='blink',
                         help="Format according to Chromium's Python coding styles instead of Blink's.")
     parser.add_argument('--no-backups', action='store_false', default=True, dest='backup',
                         help='Do not back up files before overwriting them.')
     parser.add_argument('-j', '--jobs', metavar='n', type=int, default=0,
@@ skipping 82 matching lines @@
 
     if autopep8_options:
         tmp_str = autopep8.fix_code(tmp_str, autopep8_options)
 
     if fixers:
         tool = lib2to3.refactor.RefactoringTool(fixer_names=fixers,
                                                 explicit=fixers)
         tmp_str = unicode(tool.refactor_string(tmp_str, name=name))
 
     return tmp_str