fb: slightly adjust navigationring background drawable size

for custom icons to fit the system icons

Change-Id: I068cd0a463484f0f1b3ed0f210701290be364b7a
fb: fix possible NPE on back button transition

Change-Id: Ia6e30a9d94f292e7616b846f159b61fed9f502cc
fb: refactor QuietHours code

thanks to ivisiblk for the idea

Change-Id: I223c7c72a4fc90be78eba5ac680fed6d1181a0d3
Merge "fb: refactor QuietHours code" into kk4.4-caf