Run "svn revert" in update_depot_tools --force

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
 
 :: Windows freaks out if a file is overwritten while it's being executed.  Copy
@@ skipping 20 matching lines @@
 IF "%DEPOT_TOOLS_UPDATE%" == "0" GOTO :EOF
 
 :: We need either .\.svn\. or .\.git\. to be able to sync.
 IF EXIST "%DEPOT_TOOLS_DIR%.svn\." GOTO :SVN_UPDATE
 IF EXIST "%DEPOT_TOOLS_DIR%.git\." GOTO :GIT_UPDATE
 echo Error updating depot_tools, no revision tool found.
 goto :EOF
 
 
 :SVN_UPDATE
-call svn up -q "%DEPOT_TOOLS_DIR%."
+FOR %%A IN (%*) DO (
+  IF "%%A" == "--force" (
+    call svn -q revert -R "%DEPOT_TOOLS_DIR%."
+  )
+)
+call svn -q up "%DEPOT_TOOLS_DIR%."
 goto :EOF
 
 
 :GIT_UPDATE
 cd /d "%DEPOT_TOOLS_DIR%."
 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
 if errorlevel 1 echo Failed to update depot_tools.
+goto :EOF
 
-goto :EOF
 
 :GIT_SVN_UPDATE
 cd /d "%DEPOT_TOOLS_DIR%."
 call git svn rebase -q -q
 goto :EOF