perf: Send a boost hint when a key on the navbar is pressed

 * A lot of stuff happens, especially when invoking recents.
 * Get ahead of the storm by sending a boost hint before
   kicking off the animations.

Change-Id: I0cecd0c58f8bc8479ea44f63af796500d7b9d7d2

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/policy/KeyButtonView.java