[NaCl SDK] Fix PRESUBMIT.py on Windows.

native_client_sdk/PRESUBMIT.py

 # Copyright (c) 2012 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.
 
 """Top-level presubmit script for isolate.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
 details on the presubmit API built into gcl.
 """
 
 
 def CommonChecks(input_api, output_api):
   output = []
   disabled_warnings = [
     'F0401',  # Unable to import module
     'R0401',  # Cyclic import
     'W0613',  # Unused argument
     'E1103',  # subprocess.communicate() generates these :(
     'R0201',  # method could be function (doesn't reference self)
   ]
-  black_list = [r'src/build_tools/tests/.*',
-                r'src/site_scons/.*',
-               ]
+  black_list = [r'src[\\\/]build_tools[\\\/]tests[\\\/].*']
   canned = input_api.canned_checks
   output.extend(canned.RunPylint(input_api, output_api, black_list=black_list,
                 disabled_warnings=disabled_warnings))
   return output
 
 
 def CheckChangeOnUpload(input_api, output_api):
   return CommonChecks(input_api, output_api)
 
 
 def CheckChangeOnCommit(input_api, output_api):
   return CommonChecks(input_api, output_api)
 
 
 def GetPreferredTrySlaves(project, change):
   return ['linux_nacl_sdk', 'win_nacl_sdk', 'mac_nacl_sdk']