Discover git.bat even if git_cl.py is executed using relative path

git_common.py

 # Copyright 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.
 
 # Monkeypatch IMapIterator so that Ctrl-C can kill everything properly.
 # Derived from https://gist.github.com/aljungberg/626518
 import multiprocessing.pool
 from multiprocessing.pool import IMapIterator
 def wrapper(func):
   def wrap(self, timeout=None):
@@ skipping 12 matching lines @@
 import os
 import re
 import signal
 import sys
 import tempfile
 import textwrap
 import threading
 
 import subprocess2
 
+ROOT = os.path.abspath(os.path.dirname(__file__))
 
-GIT_EXE = 'git.bat' if sys.platform.startswith('win') else 'git'
+GIT_EXE = ROOT+'\\git.bat' if sys.platform.startswith('win') else 'git'
 TEST_MODE = False
 
 FREEZE = 'FREEZE'
 FREEZE_SECTIONS = {
   'indexed': 'soft',
   'unindexed': 'mixed'
 }
 FREEZE_MATCHER = re.compile(r'%s.(%s)' % (FREEZE, '|'.join(FREEZE_SECTIONS)))
 
 
@@ skipping 663 matching lines @@
     return None
   return ret
 
 
 def upstream(branch):
   try:
     return run('rev-parse', '--abbrev-ref', '--symbolic-full-name',
                branch+'@{upstream}')
   except subprocess2.CalledProcessError:
     return None