Access environment variables through Host object instead of directly.

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 455 matching lines @@
 
     return option_parser.parse_args(args)
 
 
 def _set_up_derived_options(port, options, args):
     """Sets the options values that depend on other options values."""
     if options.batch_size is None:
         options.batch_size = port.default_batch_size()
 
     if not options.child_processes:
-        options.child_processes = os.environ.get("WEBKIT_TEST_CHILD_PROCESSES",
-                                                 str(port.default_child_processes()))
+        options.child_processes = port.host.environ.get("WEBKIT_TEST_CHILD_PROCESSES",
+                                                        str(port.default_child_processes()))
     if not options.max_locked_shards:
-        options.max_locked_shards = int(os.environ.get("WEBKIT_TEST_MAX_LOCKED_SHARDS",
-                                                       str(port.default_max_locked_shards())))
+        options.max_locked_shards = int(port.host.environ.get("WEBKIT_TEST_MAX_LOCKED_SHARDS",
+                                                              str(port.default_max_locked_shards())))
 
     if not options.configuration:
         options.configuration = port.default_configuration()
 
     if options.pixel_tests is None:
         options.pixel_tests = port.default_pixel_tests()
 
     if not options.time_out_ms:
         options.time_out_ms = str(port.default_timeout_ms())
 
@@ skipping 85 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)