Running webkit-patch rebaseline-cl crashes on Windows. I investigated and it looks like it's because when Executive.popen tries to run "git rev-parse --is-inside-work-tree" it doesn't pass shell="True" and Windows fails to run the command.

I wrote a small test script that demonstrates the problem more succinctly. Without shell="True" the script fails.

import subprocess
process = subprocess.Popen(["git", "rev-parse", "--is-inside-work-tree"], shell="True")
process.communicate()

Full output of webkit-patch rebaseline-cl:

The current directory (None) is not in a git repo, trying directory C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\common\checkout.
Failed to find Git repo for None or C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\common\checkout
Traceback (most recent call last):
  File "third_party\WebKit\Tools\Scripts\webkit-patch", line 84, in <module>
    main()
  File "third_party\WebKit\Tools\Scripts\webkit-patch", line 79, in main
    WebKitPatch(os.path.abspath(__file__)).main()
  File "C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\tool\webkit_patch.py", line 120, in main
    result = command.check_arguments_and_execute(options, args, self)
  File "C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\tool\commands\command.py", line 110, in check_arguments_and_execute
    return self.execute(options, args, tool) or 0
  File "C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\tool\commands\rebaseline_cl.py", line 56, in execute
    issue_number = self._get_issue_number()
  File "C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\tool\commands\rebaseline_cl.py", line 107, in _get_issue_number
    issue = self.git_cl().get_issue_number()
  File "C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\common\net\git_cl.py", line 51, in get_issue_number
    return self.run(['issue']).split()[2]
  File "C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\common\net\git_cl.py", line 36, in run
    return self._host.executive.run_command(command, cwd=self._cwd)
  File "C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\common\system\executive.py", line 321, in run_command
    close_fds=self._should_close_fds())
  File "C:\src\chrome\src\third_party\WebKit\Tools\Scripts\webkitpy\common\system\executive.py", line 389, in popen
    return subprocess.Popen(string_args, **kwargs)
  File "C:\src\depot_tools\python276_bin\lib\subprocess.py", line 709, in __init__
    errread, errwrite)
  File "C:\src\depot_tools\python276_bin\lib\subprocess.py", line 957, in _execute_child
    startupinfo)
WindowsError: [Error 2] The system cannot find the file specified