Fix checkout root detection for git

scm.py

 # Copyright (c) 2006-2009 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.
 
 """SCM-specific utility classes."""
 
 import os
 import re
 import shutil
 import subprocess
@@ skipping 216 matching lines @@
         diff[i] = '--- %s' % diff[i+1][4:]
     return ''.join(diff)
 
   @staticmethod
   def GetPatchName(cwd):
     """Constructs a name for this patch."""
     short_sha = GIT.Capture(['rev-parse', '--short=4', 'HEAD'], cwd).strip()
     return "%s-%s" % (GIT.GetBranch(cwd), short_sha)
 
   @staticmethod
-  def GetCheckoutRoot(cwd):
-    """Returns the top level directory of the current repository.
-
-    The directory is returned as an absolute path.
+  def GetCheckoutRoot(path):
+    """Returns the top level directory of a git checkout as an absolute path.
     """
-    return os.path.abspath(GIT.Capture(['rev-parse', '--show-cdup'],
-                                       cwd).strip())
+    root = GIT.Capture(['rev-parse', '--show-cdup'], path).strip()
+    return os.path.abspath(os.path.join(path, root))
 
 
 class SVN(object):
   COMMAND = "svn"
 
   @staticmethod
   def Run(args, in_directory):
     """Runs svn, sending output to stdout.
 
     Args:
@@ skipping 441 matching lines @@
     if not cur_dir_repo_root:
       return None
 
     while True:
       parent = os.path.dirname(directory)
       if (SVN.CaptureInfo(parent, print_error=False).get(
               "Repository Root") != cur_dir_repo_root):
         break
       directory = parent
     return directory