Change GitCL to initialize git executable name on Windows.

third_party/WebKit/Tools/Scripts/webkitpy/common/host_mock.py

 # Copyright (C) 2011 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #    * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #    * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 51 matching lines @@
         self.buildbot = MockBuildBot()
 
         # Note: We're using a real PortFactory here. Tests which don't wish to depend
         # on the list of known ports should override this with a MockPortFactory.
         self.port_factory = PortFactory(self)
 
         self.builders = BuilderList(BUILDERS)
 
     def git(self, path=None):
         if path:
-            return MockGit(cwd=path, filesystem=self.filesystem, executive=self.executive)
+            return MockGit(cwd=path, filesystem=self.filesystem, executive=self.executive, platform=self.platform)
         if not self._git:
-            self._git = MockGit(filesystem=self.filesystem, executive=self.executive)
+            self._git = MockGit(filesystem=self.filesystem, executive=self.executive, platform=self.platform)
         # Various pieces of code (wrongly) call filesystem.chdir(checkout_root).
         # Making the checkout_root exist in the mock filesystem makes that chdir not raise.
         self.filesystem.maybe_make_directory(self._git.checkout_root)
         return self._git
 
     def _add_base_manifest_to_mock_filesystem(self, filesystem):
         webkit_finder = WebKitFinder(filesystem)
 
         external_dir = webkit_finder.path_from_webkit_base('LayoutTests', 'external')
         filesystem.maybe_make_directory(filesystem.join(external_dir, 'wpt'))
 
         manifest_base_path = filesystem.join(external_dir, 'WPT_BASE_MANIFEST.json')
         filesystem.files[manifest_base_path] = '{}'