Revert "Stomp on a benefitless, probably problematic, delta that creaped in with ActiveDisplay"

This change breaks lockscreen blur.  If the screen is turned off a second time before
unlocking the device the background is only transparent the next time the screen is turned
on.

enable blur -> screen off -> screen on (blur);  screen off -> screen on (no blur);

This reverts commit 632daaabbfa4ee1c96d8265f9d9292de04c8bf4e.

Change-Id: Ie549c2848f998c5a5e36c23d008452521166d62c
Merge "Revert "Stomp on a benefitless, probably problematic, delta that creaped in with ActiveDisplay"" into kk44