- add content observer for brightness relates changes, and update the
brightness preference summary when changes occur.
- also check for VR mode and auto brightness mode when reading the
current brightness value.
Merged-In: I895d251e1dc12cb114ef00328eb8aa0075d77ab1
Change-Id: Ice549ffd708c2dad311a87b6a92bf1c8db426456
Fix: 37227609
Test: make RunSettingsRoboTests
Get the current brightness level from settings provider and set it to
the brightness preference summary.
Change-Id: Ieb4fbc132ec120cf839548f64e9c5f5b52b2f9c2
Fix: 36650108
Test: make RunSettingsRoboTests