Fix a bug in ListView where touch scrolling could skip a data set change

Bug 2597058

ListView's touch scrolling can query the adapter for new views. As we now
flush pending touch events before running layout/draw traversals (when we
normally bring ListView back in sync), this can now happen more often.

Resync data before executing a scroll if a data set change is pending.

Change-Id: I3e4eba4c2537911ba9cb3393ee4d9e68e46f84bb

Author: adamp

core/java/android/widget/AbsListView.java

@@ -3179,6 +3179,13 @@ public boolean onTouchEvent(MotionEvent ev) {
                 mActivePointerId = ev.getPointerId(pointerIndex);
             }
             final int y = (int) ev.getY(pointerIndex);
+
+            if (mDataChanged) {
+                // Re-sync everything if data has been changed
+                // since the scroll operation can query the adapter.
+                layoutChildren();
+            }
+
             switch (mTouchMode) {
             case TOUCH_MODE_DOWN:
             case TOUCH_MODE_TAP: