Don't invalidate list data during layout.

When a FastScroller is enabled, we were invalidating the
list data during layout, which left the UI in a bad state.
Long-presses didn't work properly, and TalkBack touches
were impossible to perform.

Bug: 31160338

Test: Manually tested long pressing, and verified
that TalkBack now works with the TestActivity in ag/1567328.
Change-Id: Iecd2d597259748a3ecbf5573950e565a0e9faa42

core/java/android/widget/AbsListView.java

@@ -2160,7 +2160,6 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
         }
 
         layoutChildren();
-        mInLayout = false;
 
         mOverscrollMax = (b - t) / OVERSCROLL_LIMIT_DIVISOR;
 
@@ -2168,6 +2167,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
         if (mFastScroll != null) {
             mFastScroll.onItemCountChanged(getChildCount(), mItemCount);
         }
+        mInLayout = false;
     }
 
     /**
@@ -2697,6 +2697,9 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
      * fail to relayout them properly to accommodate for new bounds.
      */
     void handleBoundsChange() {
+        if (mInLayout) {
+            return;
+        }
         final int childCount = getChildCount();
         if (childCount > 0) {
             mDataChanged = true;