Use new common utils where possible.

slave/skia_slave_scripts/chrome_drt_canary_run_webkit_tests.py

 #!/usr/bin/env python
 # Copyright (c) 2013 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.
 
 """ Run the WebKit tests. """
 
 from build_step import BuildStep, BuildStepWarning
-from utils import shell_utils
+from py.utils import shell_utils
 import os
 import sys
 
 
 class ChromeDRTCanaryRunWebkitTests(BuildStep):
   def __init__(self, timeout=16800, no_output_timeout=16800, **kwargs):
     super(ChromeDRTCanaryRunWebkitTests, self).__init__(
         timeout=timeout, no_output_timeout=no_output_timeout, **kwargs)
 
   def _Run(self):
@@ skipping 14 matching lines @@
     try:
       shell_utils.run(cmd)
     except Exception as e:
       # Allow this step to fail with a warning, since we expect to see a lot of
       # failures which aren't our fault. Instead, we care about the diffs.
       raise BuildStepWarning(e)
 
 
 if '__main__' == __name__:
   sys.exit(BuildStep.RunBuildStep(ChromeDRTCanaryRunWebkitTests))