Consistency for: * Early return on calling setter with the current state * Calling setWillNotDraw when divider is configured with drawable and visible * Calling requestLayout to trigger a relayout pass Also fix a bug that wouldn't show end divider when all non-GONE children have 0 width/height. Bug: 28398719 Bug: 28404367 Change-Id: I16796c74a52ac4c3041390c75add2ec3c33bea8b