Revert of Removed virtualenv from depot_tools

bootstrap/virtualenv/virtualenv_embedded/activate.bat

Index: bootstrap/virtualenv/virtualenv_embedded/activate.bat
diff --git a/bootstrap/virtualenv/virtualenv_embedded/activate.bat b/bootstrap/virtualenv/virtualenv_embedded/activate.bat
new file mode 100644
index 0000000000000000000000000000000000000000..4c2003ef5e9ba0c10d59b40f863d4ed9a8e3fa14
--- /dev/null
+++ b/bootstrap/virtualenv/virtualenv_embedded/activate.bat
@@ -0,0 +1,26 @@
+@echo off
+set "VIRTUAL_ENV=__VIRTUAL_ENV__"
+
+if defined _OLD_VIRTUAL_PROMPT (
+    set "PROMPT=%_OLD_VIRTUAL_PROMPT%"
+) else (
+    if not defined PROMPT (
+        set "PROMPT=$P$G"
+    )
+	set "_OLD_VIRTUAL_PROMPT=%PROMPT%"	
+)
+set "PROMPT=__VIRTUAL_WINPROMPT__ %PROMPT%"
+
+if not defined _OLD_VIRTUAL_PYTHONHOME (
+    set "_OLD_VIRTUAL_PYTHONHOME=%PYTHONHOME%"
+)
+set PYTHONHOME=
+
+if defined _OLD_VIRTUAL_PATH (
+    set "PATH=%_OLD_VIRTUAL_PATH%"
+) else (
+    set "_OLD_VIRTUAL_PATH=%PATH%"
+)
+set "PATH=%VIRTUAL_ENV%\__BIN_NAME__;%PATH%"
+
+:END