GridLayoutManager: fix some animation jumpiness

Looks like a typo that cause secondarySize is not updated in onMeasure()
and later a posted Runnable update the secondarySize.

Also focused item maybe out of bounds if we scroll really fast.  So
we should measure every child.

part of b/15413508
b/14885970

Change-Id: I7478ea39f1fb429f483b5f25b69118b66c086c21
1 file changed