Frameworks: Lockscreen Blur

  If user selects "See through" under screen security,
  the locksceen background will now appear transparent
  with the content behind it blurred.

Modificaitons made to the orginal commit to support Hammerhead and Flo.
It seems full HD images causes rendering artifacts. To prevent this,
we scale the image size to something more manageable.

PS2: Reduce calls to System.Settngs
     Move bitmap scaling to DisplayPowerController
PS3: Fix styling
PS4: Fixes: 1. Black wallpaper after turning off see through
            2. Wallpaper flicker on unlock when blur is enabled
PS5: Ignore status bar and nav bar when capturing screenshots
PS6: 1. Remove content observer and unnecessary calls from viewManager
     2. Restructure the flow of setting the custom image
         * now closely follows setting album art as lockscreen image

Fix: Ensure lockscreen see through setting persists after reboot

If see through was enabled and the device was rebooted,
the user had to toggle the setting off and on again to activate.

Change-Id: I651a843241d2a0fa8f0f41e5c6b4415012d1635a

Keyguard: smooth background change.

Change-Id: Ia0e4d0000db72b5cdb6fede03791805e34fa311d

Fix: resolve black screen caused by lockscreen blur revert

Change-Id: Iaea865bbbcd81caf699b6c282da84816f7a4378a