[On-device adaptive brightness] Cancel brightness change if old & new are the same

Bug: 881215
Change-Id: Idce875648aa8736e8c025f266f6c8d06f32be345
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1623646
Commit-Queue: Jia Meng <jiameng@chromium.org>
Reviewed-by: Michael Martis <martis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662919}
1 file changed