The layertype was incorrectly restored with overlapping alpha animations.

This could lead to weird clipping bugs on the lockscreen. We now simply
set its type to back to NONE after the animation.

Bug: 15186220
Change-Id: I884b6830d748309105ed62471cb8b6dee71d51fe

packages/SystemUI/src/com/android/systemui/statusbar/stack/StackStateAnimator.java

@@ -315,14 +315,13 @@ public class StackStateAnimator {
                 child.getAlpha(), newEndValue);
         animator.setInterpolator(mFastOutSlowInInterpolator);
         // Handle layer type
-        final int currentLayerType = child.getLayerType();
         child.setLayerType(View.LAYER_TYPE_HARDWARE, null);
         animator.addListener(new AnimatorListenerAdapter() {
             public boolean mWasCancelled;
 
             @Override
             public void onAnimationEnd(Animator animation) {
-                child.setLayerType(currentLayerType, null);
+                child.setLayerType(View.LAYER_TYPE_NONE, null);
                 if (newEndValue == 0 && !mWasCancelled) {
                     child.setVisibility(View.INVISIBLE);
                 }