Simplify the initialization of Git objects in Host.

third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/scm/git_mock.py

 # Copyright 2016 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.
 
 from webkitpy.common.system.filesystem_mock import MockFileSystem
 from webkitpy.common.system.executive_mock import MockExecutive
 
 
 class MockGit(object):
 
     # Arguments are listed below, even if they're unused, in order to match
     # the Git class. pylint: disable=unused-argument
 
     executable_name = 'mock-git'
 
-    def __init__(self, filesystem=None, executive=None):
+    def __init__(self, cwd=None, filesystem=None, executive=None):
         self.checkout_root = '/mock-checkout'
+        self.cwd = cwd or self.checkout_root
         self.added_paths = set()
         self._filesystem = filesystem or MockFileSystem()
         self._executive = executive or MockExecutive()
         self._local_commits = []
 
     def add_all(self, pathspec=None):
         if not pathspec:
             pathspec = self.checkout_root
         for path in self._filesystem.glob(pathspec):
             self.add_list(self._filesystem.files_under(path))
@@ skipping 76 matching lines @@
 
     def move(self, origin, destination):
         if self._filesystem:
             self._filesystem.move(self.absolute_path(origin), self.absolute_path(destination))
 
     def changed_files(self):
         return []
 
     def unstaged_changes(self):
         return {}