Add a dedicated pretty-diff command.

sky/tools/webkitpy/common/checkout/scm/git.py

 # Copyright (c) 2009, 2010, 2011 Google Inc. All rights reserved.
 # Copyright (c) 2009 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.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 14 matching lines @@
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 import datetime
 import logging
 import os
 import re
 
+# This import isn't used, but it's needed for the
+# path_to_module('webkitpy.common.config') call in create_patch.
+import webkitpy.common.config
+
 from webkitpy.common.checkout.scm.scm import SCM
 from webkitpy.common.memoized import memoized
 from webkitpy.common.system.executive import Executive, ScriptError
 
 _log = logging.getLogger(__name__)
 
 
 class AmbiguousCommitError(Exception):
     def __init__(self, num_local_commits, has_working_directory_changes):
         Exception.__init__(self, "Found %s local commits and the working directory is %s" % (
@@ skipping 273 matching lines @@
         if self.current_branch() != self._branch_tracking_remote_master():
             return False
         if len(self._local_commits(self._branch_tracking_remote_master())) > 0:
             return False
         return True
 
     def ensure_cleanly_tracking_remote_master(self):
         self._discard_working_directory_changes()
         self._run_git(['checkout', '-q', self._branch_tracking_remote_master()])
         self._discard_local_commits()