SystemUI: more SlimDim performance boosts

using ObjectAnimator to animate alpha value rather than
        animating the View object itself.  This allows to
        specify frame delay, which we're setting to 100ms
        (should perform better than the default 10ms).

patchset: remove listeners on animation end and cancel

patchset: disable SlimDim on lockscreen and while
        expanded desktop is enabled

patchset: fix potential NPE if expanded desktop was
        never previously enabled

patchset: more than one way to skin a cat

Change-Id: Id4d484caaab5674981e78a8ae9ca63352d792207
1 file changed