login: Use android-data directory in /home/root.

We are moving android-data directory from the current fixed
path (/home/chronos/user/android-data) to a path inside
mounted cryptohome (/home/root/<CryptohomeID>/android-data).

Note that the parameter of StartArcInstance() D-Bus method
has already been converted from socket_path to user_id in
following Chrome change:
https://codereview.chromium.org/2023803003/

CQ-DEPEND=CL:*264405
CQ-DEPEND=CL:*264339
CQ-DEPEND=CL:*261224
BUG=b:26700652
TEST=cros_run_unit_tests --board $BOARD --packages chromeos-login

Change-Id: Icc77fe5d7da07ed0986e00fc05c80032056c3631
Reviewed-on: https://chromium-review.googlesource.com/351130
Commit-Ready: Shuhei Takahashi <nya@chromium.org>
Tested-by: Shuhei Takahashi <nya@chromium.org>
Reviewed-by: Shuhei Takahashi <nya@google.com>
5 files changed