Allow seeding the random layout test order and write out seed.

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests.py

 # Copyright (C) 2010 Google Inc. All rights reserved.
 # Copyright (C) 2010 Gabor Rapcsanyi (rgabor@inf.u-szeged.hu), University of Szeged
 # Copyright (C) 2011 Apple 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.
@@ skipping 315 matching lines @@
                 help="Set the maximum number of locked shards"),
             optparse.make_option(
                 "--nocheck-sys-deps",
                 action="store_true",
                 default=False,
                 help="Don't check the system dependencies (themes)"),
             optparse.make_option(
                 "--order",
                 action="store",
                 default="natural",
-                help=("determine the order in which the test cases will be run. "
+                help=("Determine the order in which the test cases will be run. "
                       "'none' == use the order in which the tests were listed "
                       "either in arguments or test list, "
                       "'natural' == use the natural order (default), "
-                      "'random-seeded' == randomize the test order using a fixed seed, "
-                      "'random' == randomize the test order.")),
+                      "'random' == pseudo-random order. Seed can be specified "
+                      "via --seed, otherwise a default seed will be used.")),
             optparse.make_option(
                 "--profile",
                 action="store_true",
                 help="Output per-test profile information."),
             optparse.make_option(
                 "--profiler",
                 action="store",
                 help="Output per-test profile information, using the specified profiler."),
             optparse.make_option(
                 "--repeat-each",
@@ skipping 23 matching lines @@
                 help="Run a specified chunk (n:l), the nth of len l, of the layout tests"),
             optparse.make_option(
                 "--run-part",
                 help="Run a specified part (n:m), the nth of m parts, of the layout tests"),
             optparse.make_option(
                 "--run-singly",
                 action="store_true",
                 default=False,
                 help="DEPRECATED, same as --batch-size=1 --verbose"),
             optparse.make_option(
+                "--seed",
+                type="int",
+                default=4,  # http://xkcd.com/221/
+                help=("Seed to use for random test order (default: %default). "
+                      "Only applicable in combination with --order=random.")),
+            optparse.make_option(
                 "--skipped",
                 action="store",
                 default=None,
                 help=("control how tests marked SKIP are run. "
                       "'default' == Skip tests unless explicitly listed on the command line, "
                       "'ignore' == Run them anyway, "
                       "'only' == only run the SKIP tests, "
                       "'always' == always skip, even if listed on the command line.")),
             optparse.make_option(
                 "--fastest",
@@ skipping 182 matching lines @@
             _log.debug("\t%s", process)
 
         return run_details
 
     finally:
         printer.cleanup()
 
 if __name__ == '__main__':
     exit_code = main(sys.argv[1:], sys.stdout, sys.stderr)
     sys.exit(exit_code)