Don't mark list headers or invalid items as disabled.

Bug: 6581689
Change-Id: I4088cdc7e785e60fe7e30807cdf045131584f29d

Author: alanv

core/java/android/widget/AbsListView.java

@@ -2283,14 +2283,10 @@ public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfo i
             final ListAdapter adapter = getAdapter();
 
             if ((position == INVALID_POSITION) || (adapter == null)) {
-                // Cannot perform actions on invalid items.
-                info.setEnabled(false);
                 return;
             }
 
             if (!isEnabled() || !adapter.isEnabled(position)) {
-                // Cannot perform actions on invalid items.
-                info.setEnabled(false);
                 return;
             }