make cryptohome check a magic file to discern between chrome-login and slim-login

src/platform/cryptohome/lib/common

 #!/bin/bash
 # Copyright (c) 2009 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.
 #
 # common file containing shared globals and
 # necessary inclusions for chromeos-cryptohome
 # mounting and unmounting.
 
 # Configurable globals
 export IMAGE_DIR=/home/.shadow
 export MOUNT_OPTIONS="nosuid,noexec,nodev"
 export LOG_FILE=/var/log/cryptohome.log
 export STDOUT_FILE=/var/log/cryptohome.stdout.log
 export STDERR_FILE=/var/log/cryptohome.stderr.log
 
 export DEFAULT_USER=chronos
 export DEFAULT_LOOP_DEVICE=/dev/loop0
 export DEFAULT_MAPPER_DEVICE=/dev/mapper/cryptohome
-export DEFAULT_MOUNT_POINT=/home/$DEFAULT_USER
+
+# temporary hack to check if we're doing chrome-login
+CHROME_LOGIN_FILE=/tmp/doing-chrome-login
+MOUNT_POINT=/home/$DEFAULT_USER
+if [ -f ${CHROME_LOGIN_FILE} ]; then
+  MOUNT_POINT=${MOUNT_POINT}/user
+fi
+
+export DEFAULT_MOUNT_POINT=${MOUNT_POINT}
 
 # If the variable is defined and the file exists,
 # encryption will be disabled for users listed in the
 # file.  The file should take the format:
 #   user@domain<NEWLINE>
 #   user2@domain<NEWLINE>
 #   ...
 export DISABLED_ENCRYPTION_FILE="$IMAGE_DIR/users"
 
 # TODO: support multiple wrapped master key instances for easy
@@ skipping 13 matching lines @@
 # Pull in requirements
 PATH=/bin:/sbin:/usr/bin:/usr/sbin
 source $location/utils/declare_commands
 source $location/cryptohome
 
 # Fire up the tests.
 if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
   echo "Error: common should not be called directly" 1>&1
   exit 1
 fi