Merge changes from topic 'headsup'
* changes:
Finishing up heads up changes
Added the heads up scrim back
Fixed a bug where a notification could not be collapsed
Made ranking consistent with heads Up manager
Fixed a bug where the intrinsic height was not updated
Fixed more heads up bugs
More Heads Up bug fixes
Adapted the interpolator of the heads up appear motion
Treating headsUpViews now as real notification citizen
Handling a few more border cases with HUNs
Integrate Heads-up notifications into the shade
Fixed a bug with notification clipping