[On-device adaptive brightness] Only store ALS values after init success.

Due to potential race condition, this cl checks Adapter and ModellerImpl
are successfully initialized before storing ALS values (coming from AlsReader).

Bug: 940467
Change-Id: I62070bc9023a319deef1a917d9cdb7cd918a2521
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1516114
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Jia Meng <jiameng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#639719}
2 files changed