Fix FastTrack recycling consistency issues, shadows.

When FastTrack is displayed and a configuration change
occurs, we tear down and recreate the host Activity, but in
the process moveTaskToBack(), which means the next trigger
will show a stale track and rectangle.

This change dismisses the track in onPause() to reduce risk
of bringing back a stale track.  It also introduces a new
mDismissed flag to catch any race conditions where the track
is dismissed before showInternal() is called.

When requested a show() and already visible, instead of
ignoring, I'm calling dismissInternal() to replace the track
with the updated request.  I'm also using query tokens to
ignore query results from stale show() requests.

This change also fixes padding in the large FT format when
no photo is available.  It also fixes shadow behind track
to remove sharp vertical edges visible during animations.

Also clears "make default" checkbox between recycles and
fixes an issue where icons for preferred apps remained after
the user selects "always use" from intent disambig list.

Fixes http://b/2163611 and http://b/2164119