webkitpy: Make all regex strings use raw string literals.

third_party/WebKit/Tools/Scripts/webkitpy/style/checkers/python.py

 # Copyright (C) 2010 Chris Jerdonek (cjerdonek@webkit.org)
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 # 1.  Redistributions of source code must retain the above copyright
 #     notice, this list of conditions and the following disclaimer.
 # 2.  Redistributions in binary form must reproduce the above copyright
 #     notice, this list of conditions and the following disclaimer in the
 #     documentation and/or other materials provided with the distribution.
@@ skipping 84 matching lines @@
         FALSE_POSITIVES = [
             # possibly http://www.logilab.org/ticket/98613 ?
             "Instance of 'Popen' has no 'poll' member",
             "Instance of 'Popen' has no 'returncode' member",
             "Instance of 'Popen' has no 'stdin' member",
             "Instance of 'Popen' has no 'stdout' member",
             "Instance of 'Popen' has no 'stderr' member",
             "Instance of 'Popen' has no 'wait' member",
         ]
 
-        lint_regex = re.compile('([^:]+):([^:]+): \[([^]]+)\] (.*)')
+        lint_regex = re.compile(r'([^:]+):([^:]+): \[([^]]+)\] (.*)')
         errors = []
         for line in output.splitlines():
             if any(msg in line for msg in FALSE_POSITIVES):
                 continue
 
             match_obj = lint_regex.match(line)
             if not match_obj:
                 continue
 
             line_number = int(match_obj.group(2))
             category_and_method = match_obj.group(3).split(', ')
             category = 'pylint/' + (category_and_method[0])
             if len(category_and_method) > 1:
                 message = '[%s] %s' % (category_and_method[1], match_obj.group(4))
             else:
                 message = match_obj.group(4)
             errors.append((line_number, category, message))
         return errors