Fix SurfaceViewPositionListener race bugs

Bug: 29628138

1: Make windowPositionLost synchronous as that's
what the Java side was expecting

2: Make the listener ref counted as otherwise
there's a race condition with the GC, which could
end up with use-after-frees

3: Ensure that all position updates are invoked
prior to frame completion

Change-Id: Iedbc017f611ba2878a49b4586612f79249ca2fe3