Fix git depot_tools update flow.

gclient.bat

 @echo off
-:: Copyright (c) 2009 The Chromium Authors. All rights reserved.
+:: Copyright (c) 2012 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.
 
-:: This file is a stub to sync .\bootstrap first and defer control to
-:: .\bootstrap\gclient.bat, which will sync back '.'. This is unless auto
-:: update is disabled, were gclient.py is directly called.
-setlocal
+:: Synchronize the root directory before deferring control back to gclient.py.
+call "%~dp0\update_depot_tools.bat"
 
-:: This is required with cygwin only.
-PATH=%~dp0;%PATH%
-
-:: Will download svn and python.
-:: If you don't want to install the depot_tools version of these tools, remove
-:: the 'force' option on the next command. The tools won't be installed only if
-:: not already in the PATH environment variable.
-call "%~dp0bootstrap\win\win_tools.bat" force
-if errorlevel 1 goto :EOF
-
-:: Shall skip automatic update?
-IF "%DEPOT_TOOLS_UPDATE%" == "0" GOTO :SKIP_UPDATE
-:: We can't sync if .\.svn\. doesn't exist.
-IF NOT EXIST "%~dp0.svn\." GOTO :SKIP_UPDATE
-
-:: Sync the bootstrap directory.
-call svn up -q "%~dp0bootstrap"
-:: still continue even in case of error.
-goto :UPDATE
-
-
-:SKIP_UPDATE
-:: Don't bother to try to update any thing.
+:: Defer control.
 python "%~dp0\gclient.py" %*
-goto :EOF
-
-
-:UPDATE
-:: Transfer control to ease the update process. The following lines won't be
-:: executed so don't add any! Specifically, don't use 'call' in the following
-:: line.
-"%~dp0bootstrap\gclient.bat" %*
-goto :EOF