tree a0b8c826ec1b60d6a2cc0ff791e71dc9f78f7258
parent d812d4c1ac4590e98d41c01fab14f654ea0b3657
author Ying Zheng <yizheng@google.com> 1529449265 -0700
committer Ying Zheng <yizheng@google.com> 1529538127 -0700

Complete the logic around last active user, including:

- Update CarSettings last active user when user switched.
- Boot into the last active user if valid, or boot into the smallest
user id.
- Not allow deleting the last admin user, so we have a user 10+ to boot
into.

Test: Unit test
Bug: 110156344,110425490,110425354
Change-Id: I3e85805bf469bd17709973936e8c3285c8f44207