Add GetModifiedFiles() function to git_utils.

py/utils/git_utils.py

 #!/usr/bin/env python
 # Copyright (c) 2014 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.
 
 """This module contains functions for using git."""
 
 import os
 import re
 import shell_utils
@@ skipping 71 matching lines @@
   if remote:
     cmd.append(remote)
   shell_utils.run(cmd)
 
 
 def GetRemoteMasterHash(git_url):
   return shell_utils.run([GIT, 'ls-remote', git_url, '--verify',
                           'refs/heads/master']).rstrip()
 
 
+def GetModifiedFiles():
+  """Returns a list of locally modified files within the current working dir.
+  """
+  return shell_utils.run([GIT, 'ls-files', '-m']).splitlines()
+
+
 def GetCurrentBranch():
   return shell_utils.run([GIT, 'rev-parse', '--abbrev-ref', 'HEAD']).rstrip()
 
 
 class GitBranch(object):
   """Class to manage git branches.
 
   This class allows one to create a new branch in a repository to make changes,
   then it commits the changes, switches to master branch, and deletes the
   created temporary branch upon exit.
@@ skipping 134 matching lines @@
     shutil.rmtree(self._git_root)
 
   def _run_in_git_root(self, args):
     """Run an external command with cwd set to self._git_root.
 
     Returns the command's output as a byte string.
 
     Raises an Exception if the command fails.
     """
     return subprocess.check_output(args=args, cwd=self._git_root)