This provides a quick fix for http://b/2298803 (if the
in-call UI comes up while the user is holding the
windowshade, the shade sticks in place and the display
becomes unresponsive).
Merged from master (I92a824fe).
TODO: safely restore code to animate the shade closed rather
than simply causing it to disappear.
Change-Id: I53dc76fdfe86636f30f37a223a88d27a5766d3eb