Re-enable chroot passthru for AU server environment variable override

enter_chroot.sh

 #!/bin/bash
 
 # Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Script to enter the chroot environment
 
 # --- BEGIN COMMON.SH BOILERPLATE ---
 # Load common CrOS utilities.  Inside the chroot this file is installed in
@@ skipping 337 matching lines @@
 
 
 # Make sure we unmount before exiting
 trap teardown_env EXIT
 setup_env
 
 CHROOT_PASSTHRU="BUILDBOT_BUILD=$FLAGS_build_number CHROMEOS_OFFICIAL=$CHROMEOS_OFFICIAL"
 CHROOT_PASSTHRU="${CHROOT_PASSTHRU} \
 CHROMEOS_RELEASE_APPID=${CHROMEOS_RELEASE_APPID:-"{DEV-BUILD}"}"
 
+# Set CHROMEOS_VERSION_TRACK, CHROMEOS_VERSION_AUSERVER,
+# CHROMEOS_VERSION_DEVSERVER as environment variables to override the default
+# assumptions (local AU server). These are used in cros_set_lsb_release, and
+# are used by external Chromium OS builders.
+CHROOT_PASSTHRU="${CHROOT_PASSTHRU} \
+CHROMEOS_VERSION_TRACK=${CHROMEOS_VERSION_TRACK} \
+CHROMEOS_VERSION_AUSERVER=${CHROMEOS_VERSION_AUSERVER} \
+CHROMEOS_VERSION_DEVSERVER=${CHROMEOS_VERSION_DEVSERVER}"
+
 if [ -d "$HOME/.subversion" ]; then
   TARGET="/home/${USER}/.subversion"
   mkdir -p "${FLAGS_chroot}${TARGET}"
   ensure_mounted "${HOME}/.subversion" "--bind" "${TARGET}"
 fi
 
 # Configure committer username and email in chroot .gitconfig
 if [ $FLAGS_git_config -eq $FLAGS_TRUE ]; then
   git config -f ${FLAGS_chroot}/home/${USER}/.gitconfig --replace-all \
     user.name "$(cd /tmp; git var GIT_COMMITTER_IDENT | sed -e 's/ *<.*//')"
   git config -f ${FLAGS_chroot}/home/${USER}/.gitconfig --replace-all \
     user.email "$(cd /tmp; git var GIT_COMMITTER_IDENT | \
       sed -e 's/.*<\([^>]*\)>.*/\1/')"
 fi
 
 # Run command or interactive shell.  Also include the non-chrooted path to
 # the source trunk for scripts that may need to print it (e.g.
 # build_image.sh).
 sudo -- chroot "$FLAGS_chroot" sudo -i -u $USER $CHROOT_PASSTHRU \
   EXTERNAL_TRUNK_PATH="${FLAGS_trunk}" LANG=C SSH_AGENT_PID="${SSH_AGENT_PID}" \
   SSH_AUTH_SOCK="${SSH_AUTH_SOCK}" "$@"
 
 # Remove trap and explicitly unmount
 trap - EXIT
 teardown_env