Fix obscured touchable region code.

This fixes the issue where bubbles are untouchable after being opened from the shade, as well as issues with the animation CL.

The root cause here was that the obscured touchable region is only updated after an explicit call to ActivityView.onLocationChanged(). We were only calling this when the Bubble initially expanded, and at that point, the notification shade was expanded, so we set the touchable region to empty. When the shade collapses, the AV's onLocationChanged() is never called again, so the touchable region remains empty.

Fixing this is actually very easy - we originally needed to empty the touchable region when the shade was expanded because we were in its window (and didn't want to steal its touches). Now that we are in our own window, we don't need to worry about that, so the shade check can be deleted entirely.

This also adds a check for mExpanded = false, since a collapsed stack should never be able to dispatch touch events to the AV.

Test: expand bubbs from shade
Fixes: 157756567
Change-Id: I8350670f34660f6b725904309c5d6c70abb8a33e