Revert HeadsUp

Revert "HeadsUp: Fix dismiss on back key press."

This reverts commit d84e336fdcf5db5ab7116297732c316416845e3d.

Revert "SystemUI: Improve HeadsUp expanding performance."

This reverts commit 0d107ce038e322d251316c818f9a25f3ab24d934.

Revert "HeadsUp: Fix resetHeadsUpDecayTimer."

This reverts commit 802d3e7d2a6c0d7c29fa4f4a652615836bb6a3e5.

Revert "HeadsUp: Add heads up blacklist options. (1/2)"

This reverts commit cb85a9086a32906d4b65f19a7609870ce0d9836e.

Revert "HeadsUp: Clean up."

This reverts commit 6551a47c998c6892260dc45e9db7f1c66832cd33.

Change-Id: Ia93332125d670fd95172021f1b89a3f1c3e8d2e9

Revert "HeadsUp: Only remove heads up if attached to window"

This reverts commit 6a7eb48b34ef03d7eafa88921a51b2c364b1baee.

Revert "HeadsUp: Respect system decorations when adding view."

This reverts commit 9c16fe048747cf7e1249458a5bc1c8265024f015.

Revert "SystemUI: Expose heads up."

This reverts commit 6c65b35e061409b15ccccacf86d58dadbf655e26.

Change-Id: I0b624af16a081fc792b36ab0be9ad565de0005d7