Add prompt for updating remote URL to git-on-borg.

update_depot_tools.bat

 @echo off
 :: 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 batch file will try to sync the root directory.
 
 setlocal
 
+set GIT_URL=https://chromium.googlesource.com/chromium/tools/depot_tools.git
+
 :: 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 will be installed only if
 :: not already in the PATH environment variable.
 call "%~dp0bootstrap\win\win_tools.bat" force
 if errorlevel 1 goto :EOF
 :: Now clear errorlevel so it can be set by other programs later.
 set errorlevel=
 
 :: Shall skip automatic update?
 IF "%DEPOT_TOOLS_UPDATE%" == "0" GOTO :EOF
 
 :: We need either .\.svn\. or .\.git\. to be able to sync.
 IF EXIST "%~dp0.svn\." GOTO :SVN_UPDATE
 IF EXIST "%~dp0.git\." GOTO :GIT_UPDATE
 echo Error updating depot_tools, no revision tool found.
 goto :EOF
 
 
 :SVN_UPDATE
 call svn up -q "%~dp0."
 goto :EOF
 
 
 :GIT_UPDATE
 cd /d "%~dp0."
 call git config remote.origin.fetch > NUL
 if errorlevel 1 goto :GIT_SVN_UPDATE
+for /F %%x in ('git config --get remote.origin.url') DO (
+  IF not "%%x" == "%GIT_URL%" (
+    echo Your depot_tools checkout is configured to fetch from an obsolete URL
+    choice /N /T 60 /D N /M "Would you like to update it? [y/N]: "
+    IF not errorlevel 2 (
+      call git config remote.origin.url "%GIT_URL%"
+    )
+  )
+)
 call git fetch -q origin > NUL
 call git rebase -q origin/master > NUL
 goto :EOF
 
 :GIT_SVN_UPDATE
 cd /d "%~dp0."
 call git svn rebase -q -q
 goto :EOF