GitLab

Make PowerManagerClient notify its observers about
ScreenDimImminent D-Bus signals from powerd, and expose a
new method that calls powerd's DeferScreenDim D-Bus method.

Bug: 854908
Change-Id: I28db70981ad44c6073db4ef90dd94180665012af
Reviewed-on: https://chromium-review.googlesource.com/1123410Reviewed-by: Jia Meng <jiameng@chromium.org>
Commit-Queue: Dan Erat <derat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572051}