Use GetRemoteMasterHash() function instead of reinveting the wheel.

slave/skia_slave_scripts/chrome_canary_update.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.
 
 """ Check out the Skia sources. """
 
 # build_step must be imported first, since it does some tweaking of PYTHONPATH.
 from build_step import BuildStep
-from utils.git_utils import GIT
+from utils import git_utils
 from utils import shell_utils
 from utils import sync_skia_in_chrome
 import shlex
 import sys
 
 
 CHROMIUM_REPO = 'https://chromium.googlesource.com/chromium/src.git'
 
 
 class ChromeCanaryUpdate(BuildStep):
   def __init__(self, timeout=24000, no_output_timeout=4800, attempts=5,
                **kwargs):
     super(ChromeCanaryUpdate, self).__init__(
         timeout=timeout,
         no_output_timeout=no_output_timeout,
         attempts=attempts,
         **kwargs)
 
   def _Run(self):
-    chrome_rev = shlex.split(shell_utils.run(
-        [GIT, 'ls-remote', CHROMIUM_REPO,
-         'refs/heads/master']))[0]
+    chrome_rev = shlex.split(git_utils.GetRemoteMasterHash(CHROMIUM_REPO))[0]
 
     override_skia_checkout = True
     if 'AutoRoll' in self._builder_name:
       override_skia_checkout = False
 
     (got_skia_rev, got_chrome_rev) = sync_skia_in_chrome.Sync(
         skia_revision=self._revision,
         chrome_revision=chrome_rev,
         use_lkgr_skia=('use_lkgr_skia' in self._args.keys()),
         override_skia_checkout=override_skia_checkout)
     print 'Skia updated to %s' % got_skia_rev
     print 'Chrome updated to %s' % got_chrome_rev
 
 
 if '__main__' == __name__:
   sys.exit(BuildStep.RunBuildStep(ChromeCanaryUpdate))